diff --git a/Architecture.md b/Architecture.md
index 278efb8..ba8c9a2 100644
--- a/Architecture.md
+++ b/Architecture.md
@@ -96,7 +96,9 @@ src/editor/inspector/  Inspector panel, host (what a section builds into), field
                        (where a value lives — shared with the List tab),
                        one section per selection kind (asset/object/node/frame), variableRows (one row shape for
                        every variable), portSection, aspectAction, objectQueries/vectorRows/parentRow
-src/editor/panels/     AssetPanel, assetMenu (the two groups of the + menu), HierarchyPanel, Toolbar
+src/editor/panels/     AssetPanel, assetMenu (the two groups of the + menu), HierarchyPanel, Toolbar,
+                       TilemapPanel (tools, tiles and layers of the one selected tilemap, beside the scene view, #142;
+                       painting itself is SceneViewport)
 src/editor/graph/      GraphEditor (header + picker), GraphCanvas, graphView (zoom limits, grid, wheel zoom – shared with NodeBoard), EdgeLayer (curves and fold marks), graphMenus,
                        NodeView, NodePalette + paletteEntries (which also ranks a search), folding (hidden links, collapsed nodes), Breadcrumb + trail (the path into nested behaviors), beads (the run's pulses),
                        AnnotationView + annotationDrag (groups and comments: what a drag carries, each thing moved once)
@@ -108,8 +110,7 @@ src/editor/animation/  AnimationEditor (header + picker, preview over timeline),
                        RowDialog + FramesDialog (FormDialogs)
 src/editor/tile/        TileEditor (header + picker + kind), TileCanvas (every tile of the block and a sample map, animated),
                        PictureStrip (the pictures as animation steps; dropIndex is the reorder maths),
-                       TilePalette (the tiles as a grid of pictures in the tilemap section, #139)
-src/editor/inspector/  … tilemapSection (tools, tiles and layers of a placed tilemap; painting itself is SceneViewport)
+                       TilePalette (the tiles as a grid of pictures in the tilemap panel, #139)
 src/editor/statemachine/ StateMachineEditor (header + picker, on the graph canvas)
 src/editor/particles/  ParticlesEditor (graph canvas left of a preview panel, splitter between them),
                        ParticlePreview (the panel: the asset's own particles, wearing its own rows)
diff --git a/Development.md b/Development.md
index 6c1e678..03bf33f 100644
--- a/Development.md
+++ b/Development.md
@@ -12,7 +12,7 @@ npm run check        # typecheck + lint + format:check + tests, the gate CI runs
                      #   code is lost (tail's is reported), so a red run reads as green
 npm run build        # writes dist/ and regenerates index.html
 ./build.sh           # the same under `set -o pipefail`, for callers that pipe the output
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1027 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1032 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 — a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result
diff --git a/Tilemaps.md b/Tilemaps.md
index fdbf381..aad51f6 100644
--- a/Tilemaps.md
+++ b/Tilemaps.md
@@ -27,7 +27,21 @@ edge.
 
 ## Painting
 
-Select a placed tilemap; the inspector then shows a **PAINTING** section under its rows.
+Select a placed tilemap in the scene view, and the **Tilemap** panel opens to the right of the
+view, between it and the inspector (#142). It holds everything below: **PAINTING**, **TILES** and
+**LAYERS**. The inspector keeps what belongs to the object — name, asset, position, transform and
+the Columns, Rows and Tile size rows.
+
+- The panel is there only while **exactly one** placed tilemap is selected, and only on the Scene
+  tab. With nothing, another object or a second object selected, or on any other tab, it is gone
+  and the scene view has its full width. Selecting the tilemap asset in the asset panel does not
+  open it: one always paints a placed map.
+- It starts as wide as the inspector; the splitter on its left edge makes it wider or narrower.
+  Like the other splitters, the width is not saved.
+- Opening, closing or widening the panel leaves the map where it is on screen: the scene view
+  keeps its world in place rather than its centre, so the view simply shows more or less on the right.
+- **Deselecting the map puts the brush down**: the tool falls back to Select, so no invisible
+  brush is left waiting for the next map. The chosen tile and layer are kept.
 
 - **Select** leaves the scene view as it is: the map is picked up and dragged like any other object.
   This is what a tilemap starts in — a map one cannot move would be worse than a click.