Merge pull request #339 from fiddlerwoaroof/adr007/display-2c

feat(display): status messages and the view title show displays (improvise-cq1q.13)

context/code/core.md

@@ -1824,11 +1824,33 @@ beside the key and never in its place:
 - The browser's render model keeps its field names and carries the display in them
   (`RenderPageAxis.cat`, `RenderCatRow.label`), so `web/` is unchanged.
 
-Still keys: `GridLayout::row_label`/`col_label` (commands and the status line
-match on them), `edit_text`, the active-view marker, and everything status
-messages and the view title say (improvise-cq1q.13). A display change alone does
-not move `layout_fingerprint`, so it resets no cursor; no production path changes
-one yet.
+Still keys: `GridLayout::row_label`/`col_label` (commands match on them),
+`edit_text` and the active-view marker. A display change alone does not move
+`layout_fingerprint`, so it resets no cursor; no production path changes one yet.
+
+**What the third slice covers (improvise-cq1q.13):** the view title and every
+message that names a thing which exists. The title is the active view's display:
+the TUI reads `app.view().display()`, the browser `ViewListCache::display_of`
+(key when the list lacks the view). The statuses are the axis change (panel and
+tile bar), `Filter:`, `Deleted category/item`, the non-item
+refusal, and the item-add prompt. Both ends say them through the same
+`viewmodel` builders, so a wording is not spelled twice. The host reads
+`Model::category_display`/`item_display`; the client reads
+`CategoryTreeCache::category_display`/`item_display`. Each falls back to the key.
+
+**A message that names something which does not exist says what was typed.**
+`Unknown category 'x'`, `No view named "x"`, `View 'x' not found` and the
+`workbook.rs` errors are lookup misses: there is no display to find, and the typed
+text is what the person needs to correct. `Added category "x"` is optimistic and
+names what was just typed, whose display equals its key at creation. A stray
+coordinate in `non_item_refusal` is a key for the same reason; only the category
+beside it is a display. **A display must never reach a lookup**: the item-add
+mode keeps the category key (`AppMode::item_add_shown(key, shown)`) and the prompt
+alone carries the display. A formula-result refusal still says the target's key
+(improvise-cq1q.13 deferred it). A target in `_Measure` is implied by its formula
+and is no item, so it has no display to read. One in a regular category is a real
+item, but `CellId::Derived` carries only the target, so neither end can find its
+category. Both need that surrogate to carry the category first.
 
 `AxisFrame::cat_displays` is projected and validated, but nothing paints it yet
 (the corner label has no consumer); that is a gap to close when one does, not a

context/test-evidence/core.md

@@ -2222,3 +2222,81 @@ The display "Eastern Seaboard" against the key "E" gives 17, not the 4 minimum.
 Rival: `col_groups` labels a run with `g.name`. The browser test for group displays
 covered row groups only; this one folds a column frame whose group "Q1" is shown as
 "First quarter" and fails on the key.
+
+### draw::content_tests::the_grid_title_names_the_views_display_not_its_key
+
+improvise-cq1q.13, TUI half. The view is displayed "Quarterly overview of regional
+sales" under the key "Default", and the whole frame is drawn through `draw`. Rival:
+`draw_content` passes `app.view_state.active_view` to the widget; the title reads
+`View: Default` and this test fails on both assertions.
+
+### render::tests::the_title_names_the_active_views_display_not_its_key
+
+The browser half. Rival: `render_model` takes `view_name` from
+`state.view.active_view`; the test fails. The second half is the control: a view
+the list does not hold falls back to its key rather than to an empty title.
+
+### resolve::display_tests::a_panel_status_names_what_a_person_sees_not_the_keys
+
+The browser resolver's panel statuses: axis cycle, filter, delete category, delete
+item. Displays are 36 to 38 characters against keys of 4 to 6. Rivals, each run:
+the cycle status passes the key; the filter composes `SetPageSelection` with the
+item's display; the item removal names the display. Each fails here, the last two
+on the `Region/North` and `RemoveItem` assertions that pin the lookup to keys.
+
+### resolve::display_tests::a_tile_status_names_the_display
+
+Rival: the tile route passes `tile.category`; fails on the key.
+
+### resolve::display_tests::the_item_prompt_names_the_display_and_the_mode_keeps_the_key
+
+Rival: the mode is built with the display as its category
+(`item_add_shown(shown, ..)`); the prompt reads right and the commit would add to
+a category that does not exist. The test fails on `category == "Region"`.
+
+### resolve::display_tests::a_refused_cell_names_the_category_it_shows
+
+Rival: the non-item refusal gets the category key. The stray coordinate stays a key
+because it names no item and has no display.
+
+### command::cmd::panel::tests::a_panel_status_names_what_a_person_sees_not_the_keys
+
+The host half of the panel statuses and the item-add prompt. Rivals, each run: the
+axis status passes `cat_name` (fails); the filter status passes the item key
+(fails); the item-add mode is built from the display (fails on the
+`category: "Type"` assertion).
+
+Review follow-up: the same test now also pins the operands. Rivals: the host
+`RemoveCategory` and `SetPageSelection` given the display fail on the
+`RemoveCategory("Type")` and `item: "Food"` assertions. The client twin fails the
+same way on `RemoveCategory`.
+
+### command::cmd::tile::tests::a_tile_status_names_the_display_not_the_key
+
+Rival: the status formats `name`. It fails on both the present display and the
+absent key.
+
+### ui::app::non_item_key_tests::a_non_item_refusal_names_the_categorys_display
+
+Rival, run once per site: the refusal in `EditOrDrill` (the `i` key) and the one in
+`CmdContext::value_cell_key` (the `p` key) each pass the key. Each fails here.
+
+### ui::app::non_item_key_tests::a_commit_on_a_non_item_cell_names_the_categorys_display
+
+The third site, `uneditable` in `cmd/core.rs`, which only a commit reaches once an
+editor is open (`:enter-mode editing`). Rival: it passes the key; the two tests
+above stay green and this one fails.
+
+### ui::app::non_item_key_tests::a_refused_wire_write_names_the_category_it_shows
+
+The wire's own refusal in `Grids::unwritable`. Rival: the category key; fails. The
+formula arm (once a third copy of the derived wording, now `derived_refusal`) is
+pinned to its wording so the consolidation cannot change what it says.
+
+### resolve::display_tests::the_declines_an_advance_and_a_commit_reach_name_the_category_it_shows
+
+From the Opus review of #339: the browser's `declined_at` non-item arm could pass the
+key with the whole suite green. It is reached by `reopened_at` (an advance),
+`refused_here` (a commit) and `settle_declined_editor`. Rival: the arm passes
+`category`; the test fails on all three assertions, and the display is 36 characters
+against the key "Region".

crates/improvise-command/src/command/cmd/core.rs

@@ -39,7 +39,9 @@ pub fn uneditable(model: &Model, layout: &GridLayout, row: usize, col: usize) ->
             .to_string(),
         ),
         Some(CellId::Derived { target }) => Some(derived_refusal(&target)),
-        Some(CellId::NonItem { category, item }) => Some(non_item_refusal(&category, &item)),
+        Some(CellId::NonItem { category, item }) => {
+            Some(non_item_refusal(model.category_display(&category), &item))
+        }
         Some(CellId::Record(_) | CellId::Create(_) | CellId::Coordinate { .. }) | None => None,
     }
 }
@@ -133,7 +135,10 @@ impl<'a> CmdContext<'a> {
             Some(CellId::Create(_) | CellId::Coordinate { .. }) => {
                 Err(NO_VALUE_REFUSAL.to_string())
             }
-            Some(CellId::NonItem { category, item }) => Err(non_item_refusal(&category, &item)),
+            Some(CellId::NonItem { category, item }) => Err(non_item_refusal(
+                self.model.category_display(&category),
+                &item,
+            )),
             None => Err(match self.cell_key() {
                 Some(_) => NO_VALUE_REFUSAL,
                 None => NO_CELL,

crates/improvise-command/src/command/cmd/mode.rs

@@ -393,7 +393,8 @@ impl Cmd for EditOrDrill {
         // refused later, under a minibuffer that hides why (improvise-yc9r).
         if let Some(improvise_protocol::CellId::NonItem { category, item }) = ctx.cursor_cell_id() {
             return vec![effect::refuse(improvise_protocol::non_item_refusal(
-                &category, &item,
+                ctx.model.category_display(&category),
+                &item,
             ))];
         }
         vec![

crates/improvise-command/src/command/cmd/panel.rs

@@ -1,4 +1,6 @@
-use improvise_protocol::viewmodel::axis_change_status;
+use improvise_protocol::viewmodel::{
+    axis_change_status, deleted_category_status, deleted_item_status, filter_status,
+};
 
 use crate::ui::app::AppMode;
 use crate::ui::effect::{self, Effect, Panel, ViewTarget};
@@ -186,6 +188,57 @@ mod tests {
         );
     }
 
+    /// improvise-cq1q.13: evidence in `context/test-evidence/core.md`.
+    #[test]
+    fn a_panel_status_names_what_a_person_sees_not_the_keys() {
+        const TYPE: &str = "Kind of food and drink";
+        const FOOD: &str = "Foodstuffs of every sort";
+        let mut wb = two_cat_model();
+        let ty = wb.model.category_mut("Type").unwrap();
+        ty.set_display(TYPE);
+        ty.set_item_display("Food", FOOD);
+        let layout = make_layout(&wb);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&wb, &layout, &reg);
+        let expanded = std::collections::HashSet::from(["Type".to_string()]);
+        ctx.expanded_cats = &expanded;
+        let said = |effects: &[Box<dyn Effect>]| format!("{:?}", effects.last().unwrap());
+
+        ctx.cat_panel_cursor = 3;
+        assert_eq!(ctx.cat_at_cursor().as_deref(), Some("Type"), "setup");
+        assert!(said(&CycleAxisAtCursor.execute(&ctx)).contains(&format!("{TYPE} → ")));
+        assert!(said(&DeleteCategoryAtCursor.execute(&ctx)).contains(&format!("'{TYPE}'")));
+        let removal = format!("{:?}", DeleteCategoryAtCursor.execute(&ctx));
+        assert!(removal.contains("RemoveCategory(\"Type\")"), "{removal}");
+        let prompt = format!("{:?}", OpenItemAddAtCursor.execute(&ctx));
+        assert!(
+            prompt.contains(&format!("add item to {TYPE}: ")),
+            "{prompt}"
+        );
+        assert!(
+            prompt.contains("category: \"Type\""),
+            "the key stays: {prompt}"
+        );
+
+        ctx.cat_panel_cursor = 4;
+        let filtering = format!("{:?}", FilterToItem.execute(&ctx));
+        assert!(filtering.contains("item: \"Food\""), "keys: {filtering}");
+        let filter = said(&FilterToItem.execute(&ctx));
+        assert!(
+            filter.contains(&format!("Filter: {TYPE} = {FOOD}")),
+            "{filter}"
+        );
+        let delete = format!("{:?}", DeleteCategoryAtCursor.execute(&ctx));
+        assert!(
+            delete.contains(&format!("Deleted item '{FOOD}' from '{TYPE}'")),
+            "{delete}"
+        );
+        assert!(
+            delete.contains("item: \"Food\""),
+            "the effect still names the key: {delete}"
+        );
+    }
+
     #[test]
     fn cycle_panel_focus_with_no_panels_open() {
         let m = two_cat_model();
@@ -718,8 +771,12 @@ impl Cmd for CycleAxisAtCursor {
                 ViewTarget::Active,
                 cat_name.clone(),
             ))];
-            effects
-                .extend(cycled.map(|axis| effect::set_status(axis_change_status(&cat_name, axis))));
+            effects.extend(cycled.map(|axis| {
+                effect::set_status(axis_change_status(
+                    ctx.model.category_display(&cat_name),
+                    axis,
+                ))
+            }));
             effects
         } else {
             vec![effect::refuse(
@@ -738,7 +795,10 @@ impl Cmd for OpenItemAddAtCursor {
     }
     fn execute(&self, ctx: &CmdContext) -> Vec<Box<dyn Effect>> {
         if let Some(cat_name) = ctx.cat_at_cursor() {
-            vec![effect::change_mode(AppMode::item_add(cat_name))]
+            let shown = ctx.model.category_display(&cat_name).to_string();
+            vec![effect::change_mode(AppMode::item_add_shown(
+                cat_name, &shown,
+            ))]
         } else {
             vec![effect::refuse(
                 "No category selected. Press n to add a category first.",
@@ -790,7 +850,10 @@ impl Cmd for FilterToItem {
                         category: cat_name.clone(),
                         item: item_name.clone(),
                     }),
-                    effect::set_status(format!("Filter: {cat_name} = {item_name}")),
+                    effect::set_status(filter_status(
+                        ctx.model.category_display(&cat_name),
+                        ctx.model.item_display(&cat_name, &item_name),
+                    )),
                 ]
             }
             Some(CatTreeEntry::Category { .. }) => {
@@ -816,7 +879,7 @@ impl Cmd for DeleteCategoryAtCursor {
             Some(CatTreeEntry::Category { name, .. }) => {
                 vec![
                     Box::new(effect::RemoveCategory(name.clone())),
-                    effect::set_status(format!("Deleted category '{name}'")),
+                    effect::set_status(deleted_category_status(ctx.model.category_display(&name))),
                 ]
             }
             Some(CatTreeEntry::Item {
@@ -829,7 +892,10 @@ impl Cmd for DeleteCategoryAtCursor {
                         category: cat_name.clone(),
                         item: item_name.clone(),
                     }),
-                    effect::set_status(format!("Deleted item '{item_name}' from '{cat_name}'")),
+                    effect::set_status(deleted_item_status(
+                        ctx.model.item_display(&cat_name, &item_name),
+                        ctx.model.category_display(&cat_name),
+                    )),
                 ];
                 effects.extend(retreat_from_deleted_item(ctx));
                 effects

crates/improvise-command/src/command/cmd/tile.rs

@@ -8,6 +8,28 @@ mod tests {
     use super::*;
     use crate::command::cmd::test_helpers::*;
 
+    #[test]
+    fn a_tile_status_names_the_display_not_the_key() {
+        let mut m = two_cat_model();
+        m.model
+            .category_mut("Type")
+            .unwrap()
+            .set_display("Kind of food and drink");
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.tile_cat_idx = ctx
+            .view
+            .tileable_cats(&ctx.model.category_names())
+            .iter()
+            .position(|c| *c == "Type")
+            .unwrap();
+        let effects = TileAxisOp { axis: None }.execute(&ctx);
+        let said = format!("{:?}", effects.last().unwrap());
+        assert!(said.contains("Kind of food and drink → "), "{said}");
+        assert!(!said.contains("Type →"), "the key was said: {said}");
+    }
+
     #[test]
     fn tile_axis_cycle_produces_cycle_effect() {
         let m = two_cat_model();
@@ -161,7 +183,10 @@ impl Cmd for TileAxisOp {
                 }),
                 None => Box::new(effect::CycleAxis(ViewTarget::Active, name.to_string())),
             };
-            let status = format!("{} → {}", name, new_axis.plain_label());
+            let status = improvise_protocol::viewmodel::axis_change_status(
+                ctx.model.category_display(name),
+                new_axis,
+            );
             vec![axis_effect, effect::set_status(status)]
         } else {
             vec![]

crates/improvise-command/src/ui/app.rs

@@ -332,12 +332,9 @@ impl Grids<'_> {
     pub fn unwritable(&self, view: &str, cell: &RecordCell) -> Option<String> {
         let key = self.resolve_cell(view, cell)?;
         let model = &self.app.model_state.workbook.model;
-        let derived = model.formula_for(&key).map(|f| {
-            format!(
-                "{} is computed by a formula — edit the formula, not the cell",
-                f.target
-            )
-        });
+        let derived = model
+            .formula_for(&key)
+            .map(|f| crate::command::cmd::core::derived_refusal(&f.target));
         let refusal = self.app.non_item_refusal(&key).or(derived);
         refusal.or_else(|| self.aggregate_refusal(view, cell.record, &key))
     }
@@ -772,9 +769,9 @@ impl App {
     /// (improvise-b114, improvise-nacd). See `context/code/command.md`.
     fn non_item_refusal(&self, key: &CellKey) -> Option<String> {
         let model = &self.model_state.workbook.model;
-        model
-            .first_non_item(key)
-            .map(|(cat, name)| improvise_protocol::non_item_refusal(cat, name))
+        model.first_non_item(key).map(|(cat, name)| {
+            improvise_protocol::non_item_refusal(model.category_display(cat), name)
+        })
     }
 
     /// Point **this client's** slice at `name`, if the document has such a view,
@@ -5620,6 +5617,71 @@ mod non_item_key_tests {
         assert_eq!(app.view_state.status_msg, refusal("Mars"));
     }
 
+    #[test]
+    fn a_refused_wire_write_names_the_category_it_shows() {
+        const REGION: &str = "Sales territory of the whole company";
+        let mut app = paged_app("East");
+        let stray = CellKey::new(vec![
+            ("Month".into(), "Jan".into()),
+            ("Region".into(), "Mars".into()),
+            ("_Measure".into(), "Revenue".into()),
+        ]);
+        let model = &mut app.model_state.workbook.model;
+        model.set_cell(stray.clone(), CellValue::Number(2.0));
+        model.category_mut("Region").unwrap().set_display(REGION);
+        model.add_formula(
+            crate::formula::parse_formula("Profit = Revenue - 1", "_Measure").unwrap(),
+        );
+        let refused = |key: &CellKey, measure: &str| {
+            let cell = RecordCell {
+                record: RecordHash::of(key),
+                measure: Some(measure.into()),
+            };
+            app.unwritable(app.view_name(), &cell)
+        };
+        let why = refused(&stray, "Revenue").expect("a non-item is refused");
+        assert!(why.contains(REGION), "{why}");
+        assert!(
+            why.starts_with("Mars "),
+            "the stray coordinate is a key: {why}"
+        );
+        let profit = CellKey::new(vec![
+            ("Month".into(), "Jan".into()),
+            ("Region".into(), "East".into()),
+            ("_Measure".into(), "Profit".into()),
+        ]);
+        let why = refused(&profit, "Profit").expect("a formula's result is refused");
+        assert!(why.starts_with("Profit is computed by a formula"), "{why}");
+    }
+
+    #[test]
+    fn a_non_item_refusal_names_the_categorys_display() {
+        let mut app = paged_app("Mars");
+        app.model_state
+            .workbook
+            .model
+            .category_mut("Region")
+            .unwrap()
+            .set_display("Sales territory of the whole company");
+        press(&mut app, "i");
+        assert_eq!(
+            app.view_state.status_msg,
+            improvise_protocol::non_item_refusal("Sales territory of the whole company", "Mars"),
+        );
+        app.view_state.yanked = Some(CellValue::Number(7.0));
+        press(&mut app, "p");
+        assert!(
+            app.view_state
+                .status_msg
+                .ends_with(&improvise_protocol::non_item_refusal(
+                    "Sales territory of the whole company",
+                    "Mars"
+                )),
+            "{}",
+            app.view_state.status_msg
+        );
+    }
+
     /// improvise-yc9r: `p` on a non-item cell writes no orphan. Evidence file.
     #[test]
     fn p_on_a_non_item_cell_writes_nothing() {
@@ -5655,6 +5717,21 @@ mod non_item_key_tests {
         assert!(status.ends_with(&refusal("Mars")), "{status}");
     }
 
+    #[test]
+    fn a_commit_on_a_non_item_cell_names_the_categorys_display() {
+        const REGION: &str = "Sales territory of the whole company";
+        let mut app = paged_app("Mars");
+        let region = app.model_state.workbook.model.category_mut("Region");
+        region.unwrap().set_display(REGION);
+        press(&mut app, ":enter-mode editing\n");
+        press(&mut app, "5\n");
+        let said = &app.view_state.status_msg;
+        assert!(
+            said.ends_with(&improvise_protocol::non_item_refusal(REGION, "Mars")),
+            "{said}"
+        );
+    }
+
     /// `uneditable` declines a non-item cell, so an advance re-opens no editor
     /// on one (#265 meets #277). Evidence: `context/test-evidence/command.md`.
     #[test]

crates/improvise-protocol/src/lib.rs

@@ -402,7 +402,14 @@ impl AppMode {
     }
 
     pub fn item_add(category: String) -> Self {
-        let prompt = format!("add item to {category}: ");
+        let shown = category.clone();
+        Self::item_add_shown(category, &shown)
+    }
+
+    /// The prompt names the category by what a person sees; `category` stays the
+    /// key the commit adds the item to (improvise-cq1q.13).
+    pub fn item_add_shown(category: String, shown: &str) -> Self {
+        let prompt = format!("add item to {shown}: ");
         Self::ItemAdd {
             category,
             minibuf: MinibufferConfig {

crates/improvise-protocol/src/render.rs

@@ -68,8 +68,8 @@ pub enum CellId {
     NonItem { category: String, item: String },
 }
 
-/// Why a cell whose coordinate names no item takes no write. One wording for the
-/// projection's decline and the host's refusal (improvise-gk51).
+/// Why a cell naming no item takes no write (improvise-gk51). `category` is a
+/// display; `item` is the stray key, which has none (`core.md` §21).
 pub fn non_item_refusal(category: &str, item: &str) -> String {
     format!("{item} is no item of {category}, so there is no one cell to write")
 }
@@ -838,6 +838,19 @@ impl CategoryTreeCache {
     pub fn category(&self, name: &str) -> Option<&CategoryRow> {
         self.categories.iter().find(|c| c.name == name)
     }
+
+    /// What a person sees for a category key; the key when the cache lacks it.
+    /// For a message only: never pass the result to a lookup (core.md §21).
+    pub fn category_display<'a>(&'a self, name: &'a str) -> &'a str {
+        self.category(name).map_or(name, |c| c.display.as_str())
+    }
+
+    /// What a person sees for an item of `cat`; the key when either is absent.
+    pub fn item_display<'a>(&'a self, cat: &str, item: &'a str) -> &'a str {
+        self.category(cat)
+            .and_then(|c| c.items.iter().find(|i| i.name == item))
+            .map_or(item, |i| i.display.as_str())
+    }
 }
 
 /// Three mutations, because the effects are three *shapes*. `Items` and
@@ -955,6 +968,17 @@ pub struct ViewListCache {
     pub views: Vec<ViewSummary>,
 }
 
+impl ViewListCache {
+    /// What a person sees for a view key; the key when the list lacks it.
+    /// For a title or a message only, never a lookup (core.md §21).
+    pub fn display_of<'a>(&'a self, key: &'a str) -> &'a str {
+        self.views
+            .iter()
+            .find(|v| v.name == key)
+            .map_or(key, |v| v.display.as_str())
+    }
+}
+
 impl WidgetCache for ViewListCache {
     type Update = Vec<ViewSummary>;
 

crates/improvise-protocol/src/resolve.rs

@@ -7,7 +7,10 @@ use serde::{Deserialize, Serialize};
 use crate::client::{ClientState, Opened, OpenedCell, OpenedTarget};
 use crate::frame::ClientFrame;
 use crate::keymap::{Binding, Keymaps, ModeKey};
-use crate::viewmodel::{CatTreeEntry, axis_change_status, flatten_cat_tree};
+use crate::viewmodel::{
+    CatTreeEntry, axis_change_status, deleted_category_status, deleted_item_status, filter_status,
+    flatten_cat_tree,
+};
 use crate::{
     AppMode, CellId, CellValue, Command, CreateKind, FormulaId, FormulaSlot, GridExtent, HelpPage,
     KeyCode, KeyEvent, ModelCommand, Panel, RECORD_COORDS_CANNOT_BE_EMPTY, RecordCell, ViewState,
@@ -579,8 +582,9 @@ fn composed(
                         category: cat.clone(),
                     },
                 )?];
+                let shown = state.categories.category_display(&cat);
                 commands
-                    .extend(cycled.map(|axis| Command::SetStatus(axis_change_status(&cat, axis))));
+                    .extend(cycled.map(|axis| Command::SetStatus(axis_change_status(shown, axis))));
                 commands
             }
             None => vec![Command::SetStatus(
@@ -592,7 +596,10 @@ fn composed(
         "delete-formula-at-cursor" => delete_formula_at_cursor(state),
 
         "open-item-add-at-cursor" => Some(match cat_at_cursor(state) {
-            Some(cat) => vec![Command::ChangeMode(AppMode::item_add(cat))],
+            Some(cat) => {
+                let shown = state.categories.category_display(&cat).to_string();
+                vec![Command::ChangeMode(AppMode::item_add_shown(cat, &shown))]
+            }
             None => vec![Command::SetStatus(
                 "No category selected. Press n to add a category first.".to_string(),
             )],
@@ -961,7 +968,7 @@ fn edit_or_drill(state: &ClientState, mode: AppMode) -> Option<Vec<Command>> {
         // them; declining rather than `None` keeps that a door, not a hole.
         CellId::Create(_) => Some(vec![Command::SetStatus(not_yet("creating a column"))]),
         CellId::NonItem { category, item } => Some(vec![Command::SetStatus(
-            crate::non_item_refusal(category, item),
+            crate::non_item_refusal(state.categories.category_display(category), item),
         )]),
     }
 }
@@ -1400,7 +1407,10 @@ pub(crate) fn declined_at(state: &ClientState, row: usize, col: usize) -> Option
     match projected_at(state, row, col)?.id.as_ref()? {
         CellId::Aggregate(_) => Some(AGGREGATE_DECLINE.to_string()),
         CellId::Derived { target } => Some(derived_decline(target)),
-        CellId::NonItem { category, item } => Some(crate::non_item_refusal(category, item)),
+        CellId::NonItem { category, item } => Some(crate::non_item_refusal(
+            state.categories.category_display(category),
+            item,
+        )),
         CellId::Record(_) | CellId::Create(_) | CellId::Coordinate { .. } => None,
     }
 }
@@ -1613,7 +1623,7 @@ fn filter_to_item_at(state: &ClientState, index: usize) -> Option<Vec<Command>>
         Some(CatTreeEntry::Item {
             cat_name,
             item_name,
-            ..
+            display,
         }) => Some(vec![
             model(
                 state,
@@ -1631,7 +1641,10 @@ fn filter_to_item_at(state: &ClientState, index: usize) -> Option<Vec<Command>>
                     item: item_name.clone(),
                 },
             )?,
-            Command::SetStatus(format!("Filter: {cat_name} = {item_name}")),
+            Command::SetStatus(filter_status(
+                state.categories.category_display(&cat_name),
+                &display,
+            )),
         ]),
         Some(CatTreeEntry::Category { .. }) => Some(toggle_cat_expand_at(state, index)),
         None => Some(Vec::new()),
@@ -1642,14 +1655,14 @@ fn filter_to_item_at(state: &ClientState, index: usize) -> Option<Vec<Command>>
 /// row deletes the item, and an empty tree says so.
 fn delete_at_cat_cursor(state: &ClientState) -> Option<Vec<Command>> {
     match cat_tree_entry(state) {
-        Some(CatTreeEntry::Category { name, .. }) => Some(vec![
+        Some(CatTreeEntry::Category { name, display, .. }) => Some(vec![
             model(state, ModelCommand::RemoveCategory(name.clone()))?,
-            Command::SetStatus(format!("Deleted category '{name}'")),
+            Command::SetStatus(deleted_category_status(&display)),
         ]),
         Some(CatTreeEntry::Item {
             cat_name,
             item_name,
-            ..
+            display,
         }) => {
             let mut commands = vec![
                 model(
@@ -1659,7 +1672,10 @@ fn delete_at_cat_cursor(state: &ClientState) -> Option<Vec<Command>> {
                         item: item_name.clone(),
                     },
                 )?,
-                Command::SetStatus(format!("Deleted item '{item_name}' from '{cat_name}'")),
+                Command::SetStatus(deleted_item_status(
+                    &display,
+                    state.categories.category_display(&cat_name),
+                )),
             ];
             commands.extend(retreat_from_deleted_item(state));
             Some(commands)
@@ -1786,7 +1802,7 @@ fn tile_axis_at(state: &ClientState, index: usize, axis: Option<Axis>) -> Option
     };
     Some(vec![
         model(state, cmd)?,
-        Command::SetStatus(axis_change_status(&tile.category, new_axis)),
+        Command::SetStatus(axis_change_status(&tile.display, new_axis)),
     ])
 }
 
@@ -5014,3 +5030,162 @@ mod opened_editor_wire_tests {
         );
     }
 }
+
+#[cfg(test)]
+mod display_tests {
+    use super::*;
+    use crate::{
+        AxisFrame, CategoryItem, CategoryRow, CategoryTreeUpdate, CellDisplay, GridExtent,
+        GridUpdate, KeyModifiers, Projection, Snapshot, TileEntry, ViewState,
+    };
+
+    const REGION: &str = "Sales territory of the whole company";
+    const NORTH: &str = "Northern reaches and the colder coasts";
+
+    fn ev(code: KeyCode) -> KeyEvent {
+        KeyEvent::new(code, KeyModifiers::NONE)
+    }
+
+    fn shown(name: &str, display: &str) -> CategoryItem {
+        CategoryItem {
+            name: name.into(),
+            display: display.into(),
+        }
+    }
+
+    /// Every key differs from, and is far shorter than, what a person sees.
+    fn displayed(cell: Option<CellId>) -> ClientState {
+        let mut state = ClientState::default();
+        let mut first = CellDisplay::number("1");
+        first.id = cell;
+        state.bootstrap(Snapshot {
+            view: ViewState::default(),
+            seed: vec![
+                Projection::CategoryTree(CategoryTreeUpdate::Categories(vec![CategoryRow {
+                    name: "Region".into(),
+                    display: REGION.into(),
+                    items: vec![shown("North", NORTH)],
+                    axis: Axis::Row,
+                }])),
+                Projection::TileBar(vec![TileEntry {
+                    category: "Region".into(),
+                    display: REGION.into(),
+                    axis: Axis::Row,
+                    kind: crate::CategoryKind::Regular,
+                }]),
+                Projection::Grid(GridUpdate::RowFrame(AxisFrame::flat(["North"]))),
+                Projection::Grid(GridUpdate::ColFrame(AxisFrame::flat(["Total"]))),
+                Projection::Grid(GridUpdate::Cells(vec![((0, 0), first)])),
+                Projection::Grid(GridUpdate::Extent(GridExtent { rows: 1, cols: 1 })),
+                Projection::Basis(crate::basis::published(7, 3, Default::default())),
+            ],
+        });
+        state.window = (1, 1);
+        state
+    }
+
+    fn last_status(commands: Vec<Command>) -> String {
+        match commands.last() {
+            Some(Command::SetStatus(said)) => said.clone(),
+            other => panic!("no status last in {commands:?}: {other:?}"),
+        }
+    }
+
+    fn local(state: &ClientState, code: KeyCode) -> Vec<Command> {
+        match resolve(state, ev(code)) {
+            KeyOutcome::Local(commands) => commands,
+            other => panic!("{code:?} did not resolve locally: {other:?}"),
+        }
+    }
+
+    #[test]
+    fn a_panel_status_names_what_a_person_sees_not_the_keys() {
+        let mut state = displayed(None);
+        state.view.mode = AppMode::CategoryPanel;
+        state.view.expanded_cats.insert("Region".into());
+        state.view.cat_panel_cursor = 0;
+        let cycled = last_status(local(&state, KeyCode::Char(' ')));
+        assert_eq!(cycled, format!("{REGION} → Col"));
+        let removal = delete_at_cat_cursor(&state).unwrap();
+        assert!(
+            removal.iter().any(|c| matches!(c, Command::Model {
+                cmd: ModelCommand::RemoveCategory(name), ..
+            } if name == "Region")),
+            "the removal names the key: {removal:?}"
+        );
+        let deleted = last_status(removal);
+        assert_eq!(deleted, format!("Deleted category '{REGION}'"));
+
+        state.view.cat_panel_cursor = 1;
+        let filtering = filter_to_item(&state).unwrap();
+        let named: Vec<String> = filtering
+            .iter()
+            .filter_map(|c| match c {
+                Command::Model {
+                    cmd: ModelCommand::SetPageSelection { category, item, .. },
+                    ..
+                } => Some(format!("{category}/{item}")),
+                _ => None,
+            })
+            .collect();
+        assert_eq!(named, ["Region/North"], "the lookup names keys");
+        let filtered = last_status(filtering);
+        assert_eq!(filtered, format!("Filter: {REGION} = {NORTH}"));
+        let removal = delete_at_cat_cursor(&state).unwrap();
+        assert!(
+            removal.iter().any(|c| matches!(c, Command::Model {
+                cmd: ModelCommand::RemoveItem { category, item }, ..
+            } if category == "Region" && item == "North")),
+            "the removal names keys: {removal:?}"
+        );
+        let deleted = last_status(removal);
+        assert_eq!(deleted, format!("Deleted item '{NORTH}' from '{REGION}'"));
+    }
+
+    #[test]
+    fn a_tile_status_names_the_display() {
+        let mut state = displayed(None);
+        state.view.mode = AppMode::TileSelect;
+        let said = last_status(tile_axis(&state, None).unwrap());
+        assert_eq!(said, format!("{REGION} → Col"));
+    }
+
+    #[test]
+    fn the_item_prompt_names_the_display_and_the_mode_keeps_the_key() {
+        let mut state = displayed(None);
+        state.view.mode = AppMode::CategoryPanel;
+        state.view.cat_panel_cursor = 0;
+        let commands = local(&state, KeyCode::Char('a'));
+        let Some(Command::ChangeMode(AppMode::ItemAdd { category, minibuf })) = commands
+            .iter()
+            .find(|c| matches!(c, Command::ChangeMode(_)))
+        else {
+            panic!("no item-add mode in {commands:?}");
+        };
+        assert_eq!(category, "Region", "the commit adds to the KEY");
+        assert_eq!(minibuf.prompt, format!("add item to {REGION}: "));
+    }
+
+    #[test]
+    fn the_declines_an_advance_and_a_commit_reach_name_the_category_it_shows() {
+        let stray = displayed(Some(CellId::NonItem {
+            category: "Region".into(),
+            item: "Mars".into(),
+        }));
+        let want = crate::non_item_refusal(REGION, "Mars");
+        assert_eq!(declined_at(&stray, 0, 0), Some(want.clone()));
+        assert_eq!(refused_here(&stray, "commit-cell-edit"), Some(want.clone()));
+        let advanced = reopened_at(&stray, 0, 0, AppMode::Normal, false);
+        assert_eq!(advanced, vec![Command::SetStatus(want)]);
+    }
+
+    #[test]
+    fn a_refused_cell_names_the_category_it_shows() {
+        let stray = displayed(Some(CellId::NonItem {
+            category: "Region".into(),
+            item: "Mars".into(),
+        }));
+        let said = last_status(local(&stray, KeyCode::Char('i')));
+        assert!(said.contains(REGION) && said.starts_with("Mars "), "{said}");
+    }
+}

crates/improvise-protocol/src/viewmodel.rs

@@ -37,12 +37,27 @@ impl CatTreeEntry {
     }
 }
 
-/// What a moved axis says on the status line. One home: the tile bar and the
-/// category panel are two routes to one operation — improvise-25bf.
+/// What a moved axis says on the status line: one home for the tile bar and the
+/// panel (improvise-25bf). Takes displays; `core.md` §21.
 pub fn axis_change_status(category: &str, axis: Axis) -> String {
     format!("{category} → {}", axis.plain_label())
 }
 
+/// What `filter-to-item` says; both ends, so one wording (improvise-cq1q.13).
+pub fn filter_status(category: &str, item: &str) -> String {
+    format!("Filter: {category} = {item}")
+}
+
+/// What deleting a category at the panel cursor says.
+pub fn deleted_category_status(category: &str) -> String {
+    format!("Deleted category '{category}'")
+}
+
+/// What deleting an item at the panel cursor says.
+pub fn deleted_item_status(item: &str, category: &str) -> String {
+    format!("Deleted item '{item}' from '{category}'")
+}
+
 /// Flatten the category panel: a header per category, then its items when
 /// expanded. The result index is `ViewState::cat_panel_cursor`.
 pub fn flatten_cat_tree(

crates/improvise-wasm-client/src/render.rs

@@ -243,7 +243,7 @@ pub fn render_model(state: &ClientState) -> RenderModel {
         mode: improvise_protocol::mode_label(&state.view.mode).to_string(),
         status: state.view.status_msg.clone(),
         status_stands: state.status_stands(),
-        view_name: state.view.active_view.clone(),
+        view_name: state.views.display_of(&state.view.active_view).to_string(),
         doc_name: state.document.name.clone(),
         doc_dirty: state.document.dirty,
         doc_stored_as: state.document.stored_as.clone(),
@@ -883,6 +883,24 @@ mod tests {
         assert!(views[0].active, "the active view is still found by its key");
     }
 
+    #[test]
+    fn the_title_names_the_active_views_display_not_its_key() {
+        let mut client = init();
+        let state = client.state_mut();
+        state.fold(&Command::Project(Projection::ViewList(vec![ViewSummary {
+            name: "Default".into(),
+            display: "Quarterly overview of regional sales".into(),
+            axes: vec![],
+        }])));
+        state.view.active_view = "Default".into();
+        assert_eq!(
+            client.model().view_name,
+            "Quarterly overview of regional sales"
+        );
+        client.state_mut().view.active_view = "Unlisted".into();
+        assert_eq!(client.model().view_name, "Unlisted", "no display: the key");
+    }
+
     #[test]
     fn the_grid_page_bar_and_item_rows_paint_displays() {
         use improvise_protocol::{AxisFrame, CategoryItem, FrameGroup};

src/draw.rs

@@ -409,7 +409,7 @@ fn draw_content(f: &mut Frame, area: Rect, app: &App) {
         GridWidget::new(
             &grid_cache,
             app.cursor(),
-            &app.view_state.active_view,
+            app.view().display(),
             &app.layout,
             &app.view_state.mode,
             &app.view_state.search_query,
@@ -1201,6 +1201,30 @@ mod content_tests {
             .collect()
     }
 
+    /// improvise-cq1q.13: evidence in `context/test-evidence/core.md`.
+    #[test]
+    fn the_grid_title_names_the_views_display_not_its_key() {
+        let mut wb = wide_grid();
+        wb.active_view_mut()
+            .set_display("Quarterly overview of regional sales");
+        let mut app = App::new(wb, None);
+        (app.term_width, app.term_height) = (100, 24);
+        let mut terminal = Terminal::new(TestBackend::new(100, 24)).expect("test backend");
+        terminal.draw(|f| draw(f, &app)).expect("draw");
+        let text: String = terminal
+            .backend()
+            .buffer()
+            .content()
+            .iter()
+            .map(|c| c.symbol())
+            .collect();
+        assert!(
+            text.contains("View: Quarterly overview of regional sales"),
+            "the title drew something else"
+        );
+        assert!(!text.contains("View: Default"), "the key was drawn");
+    }
+
     /// improvise-gtn7.1: the cursor went behind a side panel —
     /// `context/test-evidence/tui.md`.
     #[test]

src/ui/grid.rs

@@ -23,7 +23,8 @@ pub struct GridWidget<'a> {
     /// This client's cursor in the active view (improvise-8uz). Passed in
     /// rather than read off `View`, which no longer carries per-client state.
     pub cursor: ViewCursor,
-    pub view_name: &'a str,
+    /// What the title shows: the view's display, never its key (improvise-cq1q.13).
+    pub view_display: &'a str,
     pub layout: &'a GridLayout,
     pub mode: &'a AppMode,
     pub search_query: &'a str,
@@ -36,7 +37,7 @@ impl<'a> GridWidget<'a> {
     pub fn new(
         cache: &'a GridCache,
         cursor: ViewCursor,
-        view_name: &'a str,
+        view_display: &'a str,
         layout: &'a GridLayout,
         mode: &'a AppMode,
         search_query: &'a str,
@@ -46,7 +47,7 @@ impl<'a> GridWidget<'a> {
         Self {
             cache,
             cursor,
-            view_name,
+            view_display,
             layout,
             mode,
             search_query,
@@ -444,7 +445,7 @@ impl<'a> Widget for GridWidget<'a> {
     fn render(self, area: Rect, buf: &mut Buffer) {
         let block = Block::default()
             .borders(Borders::ALL)
-            .title(format!(" View: {} ", self.view_name));
+            .title(format!(" View: {} ", self.view_display));
         let inner = block.inner(area);
         block.render(area, buf);