Vacuum: deselect what is blown out, Ctrl + wheel scrolls the bag, Ctrl+click fix (t20)

Blowing out the last of a selected material removes it from the selection,
so an emptied selection picks up what you click again. Ctrl + wheel never
zooms the page and scrolls the bag list under the mouse. A bag click while
Ctrl is held adds to the selection even if the click lacks the Ctrl flag.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/DESIGN.md

@@ -250,6 +250,11 @@ above, including:
   (no menu). Selected materials stay selected when they run out, and picking up never selects
   anything (both reverse the first t20 version). Clear: a button in the bag, clicking the only
   selected row, or gamepad B.
+  Then, after playing: blowing out the last of a material deselects it again (an empty selection
+  goes back to picking what you click; a selection kept on an empty material got in the way). A
+  material selected before you have any stays selected. Ctrl + wheel scrolls the bag instead of
+  zooming the page, and a click while Ctrl is held adds to the selection even when the click
+  arrives without the Ctrl flag (seen on the owner's Linux setup).
 
 - **Fog of war also reveals the ground around the bot (t17, 2026-10-24).** About 20 grains in every
   direction, through rock, fully clear with a soft edge. Line of sight alone hid everything inside

docs/PROJECT_MAP.md

@@ -404,7 +404,7 @@ The build menu along the bottom: categories, piece tiles and their icons.
 - functions: pieceIcon, catOf, selectBuildCat, cycleBuildCat, buildVariantChips, renderBuildBar, setupBuildBar
 - variables: BUILD_CATS, BUILD_ORDER, PIECE_ICONS, lastBuildKey, lastBuildMenu
 
-### src/ui/selection.js (241 lines)
+### src/ui/selection.js (242 lines)
 The selected tool and piece: R / Q / E, drill width, filter picker, the selection card, the bag panel.
 - functions: pieceUsesWall, setDrillWidth, tuneUnderCursor, cycleItem, cycleWall, rotate, toggleBlow, pickFilterUnderCursor, toggleFilterMat, setBrush, pieceV, pieceExtra, filterChoices, matList, filterParts, filterSentence, applyFilterRun, openFilterPicker, openWallPicker, filterBlockAt, chipCost, pieceCostNow, renderSelCard, renderBag
 - variables: lastBagKey
@@ -413,12 +413,12 @@ The selected tool and piece: R / Q / E, drill width, filter picker, the selectio
 Discovery cards, hover info (I) and the cursor label.
 - functions: showCard, howText, discoveryCard, reactionsOf, hoverInfo, renderInfo, drawCursorLabel
 
-### src/ui/input.js (80 lines)
+### src/ui/input.js (89 lines)
 Keyboard and mouse listeners.
 - functions: isTyping
 - variables: canvas
 
-### src/ui/actions.js (237 lines)
+### src/ui/actions.js (239 lines)
 What input does: overlays, F, pick, copy / cut / paste, undo, building and tool use each frame. Which overlays are on, shown as a coloured frame round the screen and a named badge
 - functions: updateOverlayUI, toggleLens, doInteract, pickUnderCursor, aimBlock, stampOrigin, selModeHeld, startPaste, stopSelectAndPaste, plural, piecesIn, doUndo, endRmbRecord, dragDirFor, blockLabel, primaryPress, primaryRelease, secondaryPress, toolTick
 - variables: ovShown

docs/agent-log.md

@@ -4,6 +4,16 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-24: t20 follow-ups: deselect when blown out, Ctrl + wheel, Ctrl+click (Claude Code)
+
+- Blowing the last of a selected material removes it from the selection (`toolTick`); materials
+  selected before you have any stay. Window `wheel` listener: Ctrl + wheel never zooms the page
+  and scrolls the scrollable panel under the mouse (the Ctrl bag list). Bag clicks add when
+  `GAME.ctrl` is set even if the click has no `ctrlKey` (owner had to hold Ctrl+Shift; not
+  reproduced in headless Chromium, which passes ctrlKey).
+- Files: `src/ui/{actions,input,selection,notebook}.js`, `test/play.py` (229 checks).
+- Tests: `run_all.py --browser` all passed.
+
 ## 2026-10-24: t20 follow-up: one selection, full list while Ctrl is held (Claude Code, Codex)
 
 - `GAME.blow` is now the selection for picking up and blowing out (`vacFilter` -2 = the selection).