feat(core,protocol): a display beside the key, painted by the three panels (improvise-cq1q.3)

- `Category`, `Item` and `View` each gain a private `display` that starts equal
  to the key and changes only through `set_display` / `set_item_display`.
- `CategoryRow`, `TileEntry` and `ViewSummary` carry `display` beside their key
  field. The key stays what commands are composed from.
- The category-panel headers, the tile bar and the view list paint the display
  in the TUI and the browser. The active-view marker still compares keys.
- No production code sets a display yet, so behaviour is unchanged.
- This is the first slice of ADR 007 step 2. The grid, page bar, records labels,
  item rows and CSV export are improvise-cq1q.12; messages and the view title
  are improvise-cq1q.13.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

context/code/core.md

@@ -1739,3 +1739,28 @@ must name both lines of a duplicate; `ClaimError` carries only the id, so the
 loader keeps the line numbers. The virtual views `_records` and `_drill` are
 not yet in `VIRTUAL_IDS`. improvise-p003 item 1 asks for them, and they arrive
 with the ADR text fix (improvise-cq1q.1) rather than ahead of it.
+
+## 21. A display beside the key (ADR 007 clause 2, improvise-cq1q.3)
+
+`Category`, `Item` and `View` each carry a private `display`. It starts equal to
+the key and changes only through `set_display` / `set_item_display`, which move
+no key. Until the re-key (improvise-cq1q.4), nothing in production calls those
+setters, so `display == name` everywhere and behaviour does not change. The
+split exists so that the re-key changes what goes *into* the key, and nothing a
+person sees moves with it.
+
+**The key travels beside the display, never in place of it.** `CategoryRow`,
+`TileEntry` and `ViewSummary` each gain a `display` field. The key field
+(`name`, `category`) stays exactly what it was, because both front ends compose
+commands from it: `resolve.rs` builds `SetAxis`, `RemoveItem` and the rest out of
+those strings. Carrying the display *in* the key field would make every
+command name a key that does not exist once the two differ. That is the gap
+improvise-cq1q.11 names, and cq1q.7 later turns these key fields into ids. The
+active-view marker in both view panels still compares keys for the same reason.
+
+**What this first slice covers:** the category panel's headers, the tile bar and
+the view list, in both front ends. Item rows, the grid frame, the page bar,
+records-mode labels, CSV export headers, status messages and the view title
+still show keys. They follow in later slices of this step, because the grid's
+label tuples are also cell coordinates (`cell_key`, `innermost_group`), so their
+display has to be added at projection time rather than in place.

context/test-evidence/core.md

@@ -1998,3 +1998,29 @@ Rival, from the same review: strip the leading `_` before the space step, so
 that ` Draft` becomes `_draft`. This test fails (`left: "_draft"`), and so does
 `generated_ids_are_distinct_well_formed_and_never_reserved`. Before this test,
 the proptest was the only thing that saw the rival.
+
+## Displays beside keys (ADR 007 clause 2, improvise-cq1q.3, first slice)
+
+Each renderer test below builds a projection whose display differs from its key.
+The test-only way to get one is `set_display`, since no production path makes
+them differ yet. Every test failed before the change, with the key drawn where
+the display should be: `left: "Region"` against `right: "Sales Area"` in the
+projection and wasm tests, and a missing "Sales Area" or "Overview" in the TUI
+buffers.
+
+### ui::project::tests::the_category_panel_shows_a_display_and_keeps_the_key_commands_name
+
+It finds the row by `name == "Region"` before asserting on the display. A rival
+that writes the display into `name` fails the lookup, which covers the half that
+keeps commands working. `_Measure` is checked to fall back to its own key.
+
+### ui::view_panel::tests::a_view_row_draws_its_display_and_marks_the_active_view_by_its_key
+
+Rival: the active marker compares `summary.display == active_view`. This test
+fails on that rival (no `▶ Overview`), because the active view is a key
+(`ViewState::active_view`) and its display differs from it.
+
+### render::tests::the_panels_paint_displays_and_keep_keys_for_what_a_command_names
+
+The browser half of the same three panels. It also asserts that the view row is
+still `active` when found by key.

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

@@ -137,6 +137,7 @@ mod tests {
     fn cat_name_works_for_both_variants() {
         let header = CatTreeEntry::Category {
             name: "Region".into(),
+            display: "Region".into(),
             item_count: 2,
             expanded: false,
             axis: crate::view::Axis::None,

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

@@ -426,6 +426,11 @@ fn non_item(category: &str, item: &str) -> CellId {
     }
 }
 
+/// What a person sees for a category key; the key itself when no category holds it.
+fn category_display<'a>(model: &'a Model, name: &'a str) -> &'a str {
+    model.category(name).map_or(name, |c| c.display())
+}
+
 /// The categories the category panel draws: **every** category, virtual ones
 /// included, with their items and their axis (improvise-vjms, gotcha 7).
 pub fn category_rows(model: &Model, view: &View) -> Vec<CategoryRow> {
@@ -434,6 +439,7 @@ pub fn category_rows(model: &Model, view: &View) -> Vec<CategoryRow> {
         .into_iter()
         .map(|name| CategoryRow {
             name: name.to_string(),
+            display: category_display(model, name).to_string(),
             items: model.effective_item_names(name),
             // `try_axis_of`, not `axis_of`: a view that has never seen a category
             // has no entry and `axis_of` panics. Unseen shows as `None`.
@@ -463,6 +469,7 @@ pub fn view_summaries(app: &App) -> Vec<ViewSummary> {
         .iter()
         .map(|(name, view)| ViewSummary {
             name: name.clone(),
+            display: view.display().to_string(),
             axes: view
                 .category_axes
                 .iter()
@@ -484,6 +491,7 @@ pub fn tiles_of(model: &Model, view: &View) -> Vec<TileEntry> {
         .into_iter()
         .map(|cat| TileEntry {
             category: cat.to_string(),
+            display: category_display(model, cat).to_string(),
             axis: view.try_axis_of(cat).unwrap_or(Axis::None),
             kind: model
                 .category(cat)
@@ -1793,6 +1801,46 @@ mod tests {
         app
     }
 
+    /// One category and the active view each shown under a display that differs from their key.
+    fn app_with_displays_unlike_their_keys() -> App {
+        let mut app = app_with_data();
+        let wb = &mut app.model_state.workbook;
+        wb.model
+            .category_mut("Region")
+            .unwrap()
+            .set_display("Sales Area");
+        wb.active_view_mut().set_display("Overview");
+        app
+    }
+
+    #[test]
+    fn the_category_panel_shows_a_display_and_keeps_the_key_commands_name() {
+        let app = app_with_displays_unlike_their_keys();
+        let rows = category_rows(&app.model_state.workbook.model, app.view());
+        let region = rows.iter().find(|r| r.name == "Region").unwrap();
+        assert_eq!(region.display, "Sales Area");
+        let measure = rows.iter().find(|r| r.name == "_Measure").unwrap();
+        assert_eq!(measure.display, "_Measure");
+    }
+
+    #[test]
+    fn a_tile_shows_a_display_and_keeps_the_key_commands_name() {
+        let app = app_with_displays_unlike_their_keys();
+        let tiles = tiles_of(&app.model_state.workbook.model, app.view());
+        let region = tiles.iter().find(|t| t.category == "Region").unwrap();
+        assert_eq!(region.display, "Sales Area");
+    }
+
+    #[test]
+    fn the_view_list_shows_a_display_and_keeps_the_key_commands_name() {
+        let app = app_with_displays_unlike_their_keys();
+        let active = app.model_state.workbook.active_view.clone();
+        let summaries = view_summaries(&app);
+        let summary = summaries.iter().find(|s| s.name == active).unwrap();
+        assert_eq!(summary.display, "Overview");
+        assert_ne!(summary.name, "Overview");
+    }
+
     /// A pivot-shaped default view plus a records-shaped second one, so a
     /// switch between them crosses the boundary `settled_mode` watches.
     fn app_with_a_records_shaped_second_view() -> App {

crates/improvise-core/src/model/category.rs

@@ -8,19 +8,27 @@ pub type ItemId = usize;
 pub struct Item {
     pub id: ItemId,
     pub name: String,
+    /// What a person sees; the key until a rename (ADR 007 clause 2).
+    display: String,
     /// Parent group name, if any
     pub group: Option<String>,
 }
 
 impl Item {
     pub fn new(id: ItemId, name: impl Into<String>) -> Self {
+        let name = name.into();
         Self {
             id,
-            name: name.into(),
+            display: name.clone(),
+            name,
             group: None,
         }
     }
 
+    pub fn display(&self) -> &str {
+        &self.display
+    }
+
     pub fn with_group(mut self, group: impl Into<String>) -> Self {
         self.group = Some(group.into());
         self
@@ -129,6 +137,8 @@ impl CategoryKind {
 pub struct Category {
     pub id: CategoryId,
     pub name: String,
+    /// What a person sees; the key until a rename (ADR 007 clause 2).
+    display: String,
     /// Items in insertion order
     pub items: IndexMap<String, Item>,
     /// Named groups (hierarchy nodes)
@@ -141,9 +151,11 @@ pub struct Category {
 
 impl Category {
     pub fn new(id: CategoryId, name: impl Into<String>) -> Self {
+        let name = name.into();
         Self {
             id,
-            name: name.into(),
+            display: name.clone(),
+            name,
             items: IndexMap::new(),
             groups: Vec::new(),
             next_item_id: 0,
@@ -151,6 +163,23 @@ impl Category {
         }
     }
 
+    pub fn display(&self) -> &str {
+        &self.display
+    }
+
+    /// Changes what a person sees and nothing else: the key does not move.
+    pub fn set_display(&mut self, display: impl Into<String>) {
+        self.display = display.into();
+    }
+
+    /// Changes an item's display; false when the category has no such item.
+    pub fn set_item_display(&mut self, item: &str, display: impl Into<String>) -> bool {
+        self.items
+            .get_mut(item)
+            .map(|i| i.display = display.into())
+            .is_some()
+    }
+
     pub fn with_kind(mut self, kind: CategoryKind) -> Self {
         self.kind = kind;
         self
@@ -264,6 +293,20 @@ mod tests {
         Category::new(0, "Region")
     }
 
+    #[test]
+    fn a_display_starts_as_the_key_and_changing_it_moves_no_key() {
+        let mut c = cat();
+        c.add_item("East");
+        assert_eq!(c.display(), "Region");
+        assert_eq!(c.items["East"].display(), "East");
+        c.set_display("Sales Area");
+        assert!(c.set_item_display("East", "Eastern"));
+        assert_eq!((c.name.as_str(), c.display()), ("Region", "Sales Area"));
+        assert_eq!(c.items["East"].display(), "Eastern");
+        assert_eq!(c.items["East"].name, "East");
+        assert!(!c.set_item_display("West", "Western"), "no such item");
+    }
+
     /// improvise-2lh: call sites ask `of_name` rather than compare literals,
     /// so both directions of the mapping must agree.
     #[test]

crates/improvise-core/src/view/types.rs

@@ -41,6 +41,8 @@ pub enum GroupFold {
 #[derive(Clone)]
 pub struct View {
     pub name: String,
+    /// What a person sees; the key until a rename (ADR 007 clause 2).
+    display: String,
     /// Axis assignment for each category
     pub category_axes: IndexMap<String, Axis>,
     /// For page axis: selected item per category
@@ -65,6 +67,7 @@ impl std::fmt::Debug for View {
         use std::collections::{BTreeMap, BTreeSet};
         let View {
             name,
+            display,
             category_axes,
             page_selections,
             hidden_items,
@@ -86,6 +89,7 @@ impl std::fmt::Debug for View {
             .collect();
         f.debug_struct("View")
             .field("name", name)
+            .field("display", display)
             .field("category_axes", category_axes)
             .field("page_selections", &pages)
             .field("hidden_items", &sorted(hidden_items))
@@ -103,9 +107,20 @@ impl View {
         VIRTUAL_VIEW_NAMES.contains(&self.name.as_str())
     }
 
+    pub fn display(&self) -> &str {
+        &self.display
+    }
+
+    /// Changes what a person sees and nothing else: the key does not move.
+    pub fn set_display(&mut self, display: impl Into<String>) {
+        self.display = display.into();
+    }
+
     pub fn new(name: impl Into<String>) -> Self {
+        let name = name.into();
         Self {
-            name: name.into(),
+            display: name.clone(),
+            name,
             category_axes: IndexMap::new(),
             page_selections: HashMap::new(),
             hidden_items: HashMap::new(),
@@ -375,6 +390,14 @@ mod tests {
     use crate::view::Axis;
     use std::num::NonZeroUsize;
 
+    #[test]
+    fn a_view_display_starts_as_the_key_and_changing_it_moves_no_key() {
+        let mut v = View::new("Default");
+        assert_eq!(v.display(), "Default");
+        v.set_display("Overview");
+        assert_eq!((v.name.as_str(), v.display()), ("Default", "Overview"));
+    }
+
     /// improvise-vw47: the count is the starting guess, never the answer.
     /// What a taken name costs: `context/test-evidence/core.md`.
     #[test]

crates/improvise-protocol/src/client.rs

@@ -514,6 +514,7 @@ mod tests {
         live.fold(&Command::Project(Projection::CategoryTree(
             CategoryTreeUpdate::Categories(vec![CategoryRow {
                 name: "Region".into(),
+                display: "Region".into(),
                 items: vec!["North".into(), "South".into()],
                 axis: Axis::Row,
             }]),
@@ -523,11 +524,13 @@ mod tests {
         ])));
         live.fold(&Command::Project(Projection::TileBar(vec![TileEntry {
             category: "Region".into(),
+            display: "Region".into(),
             kind: crate::CategoryKind::Regular,
             axis: Axis::Row,
         }])));
         live.fold(&Command::Project(Projection::ViewList(vec![ViewSummary {
             name: "Default".into(),
+            display: "Default".into(),
             axes: vec![("Region".into(), Axis::Row)],
         }])));
         live.fold(&Command::SetSelected { row: 1, col: 1 });

crates/improvise-protocol/src/reduce.rs

@@ -556,10 +556,12 @@ mod tests {
             Command::Project(Projection::Formulas(vec!["Profit = Revenue - Cost".into()])),
             Command::Project(Projection::ViewList(vec![ViewSummary {
                 name: "Default".into(),
+                display: "Default".into(),
                 axes: vec![("Region".into(), Axis::Row)],
             }])),
             Command::Project(Projection::TileBar(vec![TileEntry {
                 category: "Region".into(),
+                display: "Region".into(),
                 kind: crate::CategoryKind::Regular,
                 axis: Axis::Page,
             }])),

crates/improvise-protocol/src/render.rs

@@ -759,6 +759,8 @@ impl WidgetCache for GridCache {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct CategoryRow {
     pub name: String,
+    /// What the panel shows; `name` stays what a command names (ADR 007).
+    pub display: String,
     pub items: Vec<String>,
     pub axis: Axis,
 }
@@ -857,6 +859,8 @@ impl WidgetCache for FormulaCache {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct ViewSummary {
     pub name: String,
+    /// What the view panel shows; `name` stays what a command names.
+    pub display: String,
     /// `(category, axis)` for the categories this view displays.
     pub axes: Vec<(String, Axis)>,
 }
@@ -881,6 +885,8 @@ impl WidgetCache for ViewListCache {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct TileEntry {
     pub category: String,
+    /// What the tile shows; `category` stays what a command names.
+    pub display: String,
     pub axis: Axis,
     pub kind: CategoryKind,
 }
@@ -1072,6 +1078,7 @@ mod tests {
     fn tile(category: &str, axis: Axis, kind: CategoryKind) -> TileEntry {
         TileEntry {
             category: category.to_string(),
+            display: category.to_string(),
             axis,
             kind,
         }
@@ -1156,6 +1163,7 @@ mod tests {
     fn cat(name: &str, items: &[&str], axis: Axis) -> CategoryRow {
         CategoryRow {
             name: name.into(),
+            display: name.into(),
             items: items.iter().map(|s| (*s).to_string()).collect(),
             axis,
         }
@@ -1801,12 +1809,14 @@ mod tests {
 
         let views = ViewListCache::folded(&[vec![ViewSummary {
             name: "Default".into(),
+            display: "Default".into(),
             axes: vec![("Region".into(), Axis::Row)],
         }]]);
         assert_eq!(views.views[0].name, "Default");
 
         let tiles = TileBarCache::folded(&[vec![TileEntry {
             category: "Region".into(),
+            display: "Region".into(),
             axis: Axis::Page,
             kind: crate::CategoryKind::Regular,
         }]]);
@@ -2201,10 +2211,12 @@ mod tests {
             Projection::Formulas(vec!["Profit = Revenue - Cost".into()]),
             Projection::ViewList(vec![ViewSummary {
                 name: "Default".into(),
+                display: "Default".into(),
                 axes: vec![("Region".into(), Axis::None)],
             }]),
             Projection::TileBar(vec![TileEntry {
                 category: "Region".into(),
+                display: "Region".into(),
                 axis: Axis::Page,
                 kind: crate::CategoryKind::Regular,
             }]),
@@ -2242,6 +2254,7 @@ mod tests {
                 Projection::Formulas(vec!["Profit = Revenue - Cost".into()]),
                 Projection::TileBar(vec![TileEntry {
                     category: "Region".into(),
+                    display: "Region".into(),
                     axis: Axis::Page,
                     kind: crate::CategoryKind::Regular,
                 }]),

crates/improvise-protocol/src/resolve.rs

@@ -1892,11 +1892,13 @@ mod tests {
             crate::CategoryTreeUpdate::Categories(vec![
                 crate::CategoryRow {
                     name: "Region".into(),
+                    display: "Region".into(),
                     items: vec!["North".into(), "South".into()],
                     axis: Axis::Row,
                 },
                 crate::CategoryRow {
                     name: "Product".into(),
+                    display: "Product".into(),
                     items: vec!["Shirts".into()],
                     axis: Axis::Column,
                 },
@@ -1975,11 +1977,13 @@ mod tests {
         state.tiles.tiles = vec![
             crate::TileEntry {
                 category: "Region".into(),
+                display: "Region".into(),
                 axis: Axis::Row,
                 kind: crate::CategoryKind::Regular,
             },
             crate::TileEntry {
                 category: "Product".into(),
+                display: "Product".into(),
                 axis: Axis::Column,
                 kind: crate::CategoryKind::Regular,
             },
@@ -2334,10 +2338,12 @@ mod tests {
         state.fold(&Command::Project(Projection::ViewList(vec![
             crate::ViewSummary {
                 name: "Default".into(),
+                display: "Default".into(),
                 axes: vec![],
             },
             crate::ViewSummary {
                 name: "Plan".into(),
+                display: "Plan".into(),
                 axes: vec![],
             },
         ])));
@@ -2617,6 +2623,7 @@ mod tests {
                     .into_iter()
                     .map(|name| crate::CategoryRow {
                         name: name.into(),
+                        display: name.into(),
                         items: vec!["North".into(), "South".into()],
                         axis: Axis::Row,
                     })
@@ -2635,6 +2642,7 @@ mod tests {
             .into_iter()
             .map(|name| crate::ViewSummary {
                 name: name.into(),
+                display: name.into(),
                 axes: Vec::new(),
             })
             .collect();
@@ -2642,6 +2650,7 @@ mod tests {
             .into_iter()
             .map(|category| crate::TileEntry {
                 category: category.into(),
+                display: category.into(),
                 axis: Axis::Row,
                 kind: crate::CategoryKind::Regular,
             })
@@ -3747,6 +3756,7 @@ mod tests {
         let mut tiles = in_mode(AppMode::TileSelect);
         tiles.tiles.tiles = vec![crate::TileEntry {
             category: "Region".into(),
+            display: "Region".into(),
             axis: improvise_core::view::Axis::Row,
             kind: crate::CategoryKind::Regular,
         }];

crates/improvise-protocol/src/viewmodel.rs

@@ -11,9 +11,10 @@ use crate::render::{CategoryTreeCache, ViewSummary};
 /// so the entry list *is* what the panel draws.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum CatTreeEntry {
-    /// Category header row: name, item count, expanded?
+    /// Category header row: name (the key), what it shows, item count, expanded?
     Category {
         name: String,
+        display: String,
         item_count: usize,
         expanded: bool,
         axis: Axis,
@@ -49,6 +50,7 @@ pub fn flatten_cat_tree(
         let is_expanded = expanded.contains(&row.name);
         entries.push(CatTreeEntry::Category {
             name: row.name.clone(),
+            display: row.display.clone(),
             item_count: row.items.len(),
             expanded: is_expanded,
             axis: row.axis,
@@ -94,6 +96,7 @@ mod tests {
                 .iter()
                 .map(|(name, items)| CategoryRow {
                     name: (*name).to_string(),
+                    display: (*name).to_string(),
                     items: items.iter().map(|i| i.to_string()).collect(),
                     axis: Axis::None,
                 })
@@ -112,6 +115,7 @@ mod tests {
             tree,
             vec![CatTreeEntry::Category {
                 name: "Region".into(),
+                display: "Region".into(),
                 item_count: 2,
                 expanded: false,
                 axis: Axis::None,

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

@@ -361,7 +361,7 @@ fn view_rows(state: &ClientState) -> Option<Vec<RenderViewRow>> {
             .iter()
             .enumerate()
             .map(|(i, summary)| RenderViewRow {
-                name: summary.name.clone(),
+                name: summary.display.clone(),
                 axes: improvise_protocol::viewmodel::view_axis_summary(summary),
                 active: summary.name == state.view.active_view,
                 selected: i == state.view.view_panel_cursor,
@@ -396,7 +396,7 @@ fn tile_row(state: &ClientState) -> Vec<RenderTile> {
         .iter()
         .enumerate()
         .map(|(i, tile)| RenderTile {
-            category: tile.category.clone(),
+            category: tile.display.clone(),
             axis: tile.axis.plain_label(),
             selected: selecting && i == state.view.tile_cat_idx,
         })
@@ -468,12 +468,13 @@ impl RenderCatRow {
     fn of(entry: &CatTreeEntry, selected: bool) -> Self {
         match entry {
             CatTreeEntry::Category {
-                name,
+                display,
                 item_count,
                 expanded,
                 axis,
+                ..
             } => Self {
-                label: name.clone(),
+                label: display.clone(),
                 is_category: true,
                 axis: axis.initial().to_string(),
                 item_count: Some(*item_count),
@@ -806,11 +807,13 @@ mod tests {
                 CategoryTreeUpdate::Categories(vec![
                     CategoryRow {
                         name: "Region".into(),
+                        display: "Region".into(),
                         items: vec!["North".into(), "South".into()],
                         axis: Axis::Row,
                     },
                     CategoryRow {
                         name: "Measure".into(),
+                        display: "Measure".into(),
                         items: vec!["Revenue".into()],
                         axis: Axis::Column,
                     },
@@ -843,6 +846,39 @@ mod tests {
         );
     }
 
+    #[test]
+    fn the_panels_paint_displays_and_keep_keys_for_what_a_command_names() {
+        let mut client = init();
+        let state = client.state_mut();
+        state.fold(&Command::Project(Projection::CategoryTree(
+            CategoryTreeUpdate::Categories(vec![CategoryRow {
+                name: "Region".into(),
+                display: "Sales Area".into(),
+                items: vec!["North".into()],
+                axis: Axis::Row,
+            }]),
+        )));
+        state.fold(&Command::Project(Projection::ViewList(vec![ViewSummary {
+            name: "Default".into(),
+            display: "Overview".into(),
+            axes: vec![],
+        }])));
+        state.fold(&Command::Project(Projection::TileBar(vec![TileEntry {
+            category: "Region".into(),
+            display: "Sales Area".into(),
+            axis: Axis::Row,
+            kind: improvise_protocol::CategoryKind::Regular,
+        }])));
+        state.view.view_panel_open = true;
+        state.view.active_view = "Default".into();
+        let model = client.model();
+        assert_eq!(model.categories[0].label, "Sales Area");
+        assert_eq!(model.tiles[0].category, "Sales Area");
+        let views = model.views.expect("the view panel is open");
+        assert_eq!(views[0].name, "Overview");
+        assert!(views[0].active, "the active view is still found by its key");
+    }
+
     fn client_with_panels() -> Client {
         let mut client = init();
         client
@@ -850,10 +886,12 @@ mod tests {
             .fold(&Command::Project(Projection::ViewList(vec![
                 ViewSummary {
                     name: "Default".into(),
+                    display: "Default".into(),
                     axes: vec![("Region".into(), Axis::Row), ("_Dim".into(), Axis::Column)],
                 },
                 ViewSummary {
                     name: "Plan".into(),
+                    display: "Plan".into(),
                     axes: vec![],
                 },
             ])));
@@ -867,11 +905,13 @@ mod tests {
             .fold(&Command::Project(Projection::TileBar(vec![
                 TileEntry {
                     category: "Region".into(),
+                    display: "Region".into(),
                     axis: Axis::Row,
                     kind: improvise_protocol::CategoryKind::Regular,
                 },
                 TileEntry {
                     category: "Product".into(),
+                    display: "Product".into(),
                     axis: Axis::None,
                     kind: improvise_protocol::CategoryKind::Regular,
                 },
@@ -1192,11 +1232,13 @@ mod tests {
             .fold(&Command::Project(Projection::TileBar(vec![
                 TileEntry {
                     category: "Quarter".into(),
+                    display: "Quarter".into(),
                     axis: Axis::Page,
                     kind: improvise_protocol::CategoryKind::Regular,
                 },
                 TileEntry {
                     category: "Region".into(),
+                    display: "Region".into(),
                     axis: Axis::Column,
                     kind: improvise_protocol::CategoryKind::Regular,
                 },

src/ui/category_panel.rs

@@ -73,14 +73,15 @@ impl PanelContent for CategoryContent {
 
         match &self.tree[index] {
             CatTreeEntry::Category {
-                name,
+                display,
                 item_count,
                 expanded,
                 axis,
+                ..
             } => {
                 let indicator = if *expanded { "▼" } else { "▶" };
                 let (axis_str, axis_style) = axis_display(*axis);
-                let name_part = format!("{indicator} {name} ({item_count})");
+                let name_part = format!("{indicator} {display} ({item_count})");
                 let axis_part = format!(" [{axis_str}]");
 
                 buf.set_string(inner.x, y, &name_part, base_style);
@@ -114,6 +115,7 @@ mod tests {
         let cache = CategoryTreeCache {
             categories: vec![CategoryRow {
                 name: name.to_string(),
+                display: name.to_string(),
                 axis: Axis::Row,
                 items: vec!["x".to_string()],
             }],
@@ -129,6 +131,29 @@ mod tests {
         buf.content()[31..59].iter().map(|c| c.symbol()).collect()
     }
 
+    #[test]
+    fn a_category_header_draws_its_display_not_its_key() {
+        let cache = CategoryTreeCache {
+            categories: vec![CategoryRow {
+                name: "Region".to_string(),
+                display: "Sales Area".to_string(),
+                axis: Axis::Row,
+                items: vec!["x".to_string()],
+            }],
+        };
+        let area = Rect::new(0, 0, 30, 4);
+        let mut buf = Buffer::empty(area);
+        Panel::new(
+            CategoryContent::new(&cache, &Default::default()),
+            &AppMode::Normal,
+            0,
+        )
+        .render(area, &mut buf);
+        let row: String = buf.content()[31..59].iter().map(|c| c.symbol()).collect();
+        assert!(row.contains("Sales Area"), "{row}");
+        assert!(!row.contains("Region"), "{row}");
+    }
+
     /// improvise-8l0c — `context/test-evidence/tui.md`.
     #[test]
     fn the_axis_tag_sits_beside_a_multibyte_category_name() {

src/ui/tile_bar.rs

@@ -79,7 +79,7 @@ impl<'a> Widget for TileBar<'a> {
             .iter()
             .map(|tile| {
                 let (axis_symbol, _) = TileBar::axis_display(tile.axis);
-                format!(" [{} {axis_symbol}] ", tile.category)
+                format!(" [{} {axis_symbol}] ", tile.display)
             })
             .collect();
         let widths: Vec<u16> = labels.iter().map(|l| l.width() as u16).collect();
@@ -190,6 +190,23 @@ mod tests {
         assert_eq!(was, now);
     }
 
+    #[test]
+    fn a_tile_draws_its_display_not_its_key() {
+        let mut app = app_with_two_categories();
+        let wb = &mut app.model_state.workbook;
+        wb.model
+            .category_mut("Region")
+            .unwrap()
+            .set_display("Sales Area");
+        let cache = project::tile_bar_of(&app);
+        let area = Rect::new(0, 0, 80, 1);
+        let mut buf = Buffer::empty(area);
+        TileBar::new(&cache, &AppMode::Normal, 0).render(area, &mut buf);
+        let text = buf_text(&buf);
+        assert!(text.contains("Sales Area"), "{text}");
+        assert!(!text.contains("Region"), "{text}");
+    }
+
     /// Pins the rendered line. The equivalence test above says the *inputs*
     /// are unchanged by the migration; this says the drawing of them is.
     #[test]

src/ui/view_panel.rs

@@ -62,7 +62,7 @@ impl PanelContent for ViewContent<'_> {
         };
 
         let prefix = if is_active_view { "▶ " } else { "  " };
-        let name_text = format!("{prefix}{}", summary.name);
+        let name_text = format!("{prefix}{}", summary.display);
         let y = inner.y + index as u16;
         buf.set_string(inner.x, y, &name_text, style);
 
@@ -98,6 +98,7 @@ mod tests {
         let cache = ViewListCache {
             views: vec![ViewSummary {
                 name: view_name.to_string(),
+                display: view_name.to_string(),
                 axes: vec![("Region".to_string(), Axis::Row)],
             }],
         };
@@ -119,6 +120,25 @@ mod tests {
         );
     }
 
+    #[test]
+    fn a_view_row_draws_its_display_and_marks_the_active_view_by_its_key() {
+        use crate::protocol::ViewSummary;
+        use crate::ui::panel::Panel;
+        use ratatui::{buffer::Buffer, widgets::Widget};
+        let cache = ViewListCache {
+            views: vec![ViewSummary {
+                name: "Default".to_string(),
+                display: "Overview".to_string(),
+                axes: vec![],
+            }],
+        };
+        let area = Rect::new(0, 0, 30, 4);
+        let mut buf = Buffer::empty(area);
+        Panel::new(ViewContent::new(&cache, "Default"), &AppMode::Normal, 0).render(area, &mut buf);
+        let row: String = buf.content()[31..59].iter().map(|c| c.symbol()).collect();
+        assert!(row.contains("▶ Overview"), "{row}");
+    }
+
     fn app_with_two_views() -> App {
         let mut wb = Workbook::new("Test");
         wb.add_category("Region").unwrap();