web/src/editor/HistoryPanel.tsx

@@ -23,7 +23,9 @@ export function HistoryPanel({ gardenId, canEdit }: { gardenId: number; canEdit:
       <h2 className="text-sm font-semibold text-fg">History</h2>
 
       {history.isPending && <p className="text-sm text-muted">Loading…</p>}
-      {history.isError && <Alert>{errorMessage(history.error, 'Could not load history.')}</Alert>}
+      {history.isError && sets.length === 0 && (
+        <Alert>{errorMessage(history.error, 'Could not load history.')}</Alert>
+      )}
 
       {history.isSuccess && sets.length === 0 && (
         <p className="text-sm text-muted">
@@ -38,14 +40,23 @@ export function HistoryPanel({ gardenId, canEdit }: { gardenId: number; canEdit:
       </ol>
 
       {history.hasNextPage && (
-        <Button
-          variant="ghost"
-          className="text-sm"
-          disabled={history.isFetchingNextPage}
-          onClick={() => void history.fetchNextPage()}
-        >
-          {history.isFetchingNextPage ? 'Loading…' : 'Load older'}
-        </Button>
+        <>
+          <Button
+            variant="ghost"
+            className="text-sm"
+            disabled={history.isFetchingNextPage}
+            onClick={() => void history.fetchNextPage()}
+          >
+            {history.isFetchingNextPage ? 'Loading…' : 'Load older'}
+          </Button>
+          {/* isError stays true for a failed page even though earlier pages
+              loaded, so say so rather than leaving a button that did nothing. */}
+          {history.isError && sets.length > 0 && (
+            <p className="text-xs text-red-700 dark:text-red-400">
+              {errorMessage(history.error, "Couldn't load older entries.")}
+            </p>
+          )}
+        </>
       )}
 
       {/* Said plainly rather than discovered: deleting a garden bypasses this
@@ -118,13 +129,17 @@ function HistoryEntry({
 export function relativeTime(iso: string): string {
   const then = Date.parse(iso)
   if (Number.isNaN(then)) return iso
-  const seconds = Math.round((Date.now() - then) / 1000)
+  const seconds = (Date.now() - then) / 1000
+  // Clock skew between the server and this browser can put a just-written entry
+  // slightly in the future; that's "just now", not a negative duration.
   if (seconds < 60) return 'just now'
-  const minutes = Math.round(seconds / 60)
+  // Floor throughout: 18 hours ago is "18h ago", not "yesterday". Rounding up
+  // into the next unit reads as a bigger gap than actually elapsed.
+  const minutes = Math.floor(seconds / 60)
   if (minutes < 60) return `${minutes}m ago`
-  const hours = Math.round(minutes / 60)
+  const hours = Math.floor(minutes / 60)
   if (hours < 24) return `${hours}h ago`
-  const days = Math.round(hours / 24)
+  const days = Math.floor(hours / 24)
   if (days === 1) return 'yesterday'
   if (days < 30) return `${days}d ago`
   return new Date(then).toLocaleDateString()

web/src/editor/store.ts

@@ -103,5 +103,6 @@ export const useEditorStore = create<EditorState>((set) => ({
       armedKind: null,
       liveObject: null,
       livePlanting: null,
+      railTab: null,
     }),
 }))

web/src/lib/history.test.ts

@@ -50,10 +50,22 @@ describe('describeUndo', () => {
   const target = changeSet({ counts: [{ entityType: 'object', op: 'update', n: 3 }] })
 
   it('is a plain success when nothing conflicted', () => {
-    const out = describeUndo(target, { changeSet: changeSet({ id: 2 }), conflicts: [] })
+    const out = describeUndo(target, {
+      changeSet: changeSet({ id: 2, counts: [{ entityType: 'object', op: 'update', n: 3 }] }),
+      conflicts: [],
+    })
     expect(out).toEqual({ tone: 'ok', message: 'Undone.' })
   })
 
+  // The server answers 200 with a null change set when every revision was
+  // already a no-op — reachable by undoing a creation whose object is gone.
+  // Claiming "Undone." there reports work that didn't happen.
+  it("doesn't claim to have undone a no-op", () => {
+    const out = describeUndo(target, { changeSet: null, conflicts: [] })
+    expect(out.tone).toBe('ok')
+    expect(out.message).toBe('Nothing left to undo — this was already reversed.')
+  })
+
   // The case the issue was specific about: a partial revert really did change
   // things, so reporting a bare failure would be a lie about what applied.
   it('says how much applied and what was skipped', () => {

web/src/lib/history.ts

@@ -18,7 +18,10 @@ export type ChangeSource = z.infer<typeof changeSourceSchema>
 export const changeCountSchema = z.object({
   entityType: z.enum(['garden', 'object', 'planting']),
   op: z.enum(['create', 'update', 'delete']),
-  n: z.number(),
+  // COUNT(*) can only ever be a non-negative integer; constraining it means bad
+  // data fails loudly rather than quietly hiding an Undo button (totalChanges
+  // gates it) or rendering "1.5 beds changed".
+  n: z.number().int().nonnegative(),
 })
 export type ChangeCount = z.infer<typeof changeCountSchema>
 
@@ -188,8 +191,9 @@ export function useUndo(gardenId: number) {
 
   return {
     undo,
+    // Per change set rather than a single global flag, so one row's pending
+    // state can't disable the others.
     outcomeFor: (id: number): UndoOutcome | undefined => outcomes[id],
-    isPending: revert.isPending,
   }
 }
 
@@ -206,10 +210,14 @@ export interface UndoOutcome {
  */
 export function describeUndo(target: ChangeSet, result: RevertResult): UndoOutcome {
   const skipped = result.conflicts.map(describeConflict).join('; ')
+  const applied = result.changeSet ? totalChanges(result.changeSet) : 0
   if (result.conflicts.length === 0) {
+    // The server answers 200 with a null change set when every revision was
+    // already a no-op — reachable by undoing a creation whose object is gone.
+    // Claiming "Undone." there would be reporting work that didn't happen.
+    if (applied === 0) return { tone: 'ok', message: 'Nothing left to undo — this was already reversed.' }
     return { tone: 'ok', message: 'Undone.' }
   }
-  const applied = result.changeSet ? totalChanges(result.changeSet) : 0
   if (applied === 0) {
     return { tone: 'error', message: `Nothing was undone — ${skipped}.` }
   }

web/src/pages/GardenEditorPage.tsx

@@ -44,9 +44,6 @@ export function GardenEditorPage() {
   const setRailTab = useEditorStore((s) => s.setRailTab)
   const armedPlant = useEditorStore((s) => s.armedPlant)
   const setArmedPlant = useEditorStore((s) => s.setArmedPlant)
-  const setArmedKind = useEditorStore((s) => s.setArmedKind)
-  const setLiveObject = useEditorStore((s) => s.setLiveObject)
-  const setLivePlanting = useEditorStore((s) => s.setLivePlanting)
 
   const updatePlanting = useUpdatePlanting(gid)
   const updateObject = useUpdateObject(gid)
@@ -83,15 +80,9 @@ export function GardenEditorPage() {
   // gardens (and on leaving). `focus` is intentionally read once here, not a dep,
   // so URL syncs below don't retrigger a full reset.
   useEffect(() => {
-    const clear = () => {
-      select(null)
-      selectPlanting(null)
-      setArmedKind(null)
-      setArmedPlant(null)
-      setLiveObject(null)
-      setLivePlanting(null)
-      setRailTab(null)
-    }
+    // resetTransient is the single list of ephemeral editor state, so new state
+    // (the rail tab did exactly this) can't be forgotten here.
+    const clear = () => useEditorStore.getState().resetTransient()
     clear()
     setFocusedObject(focus ?? null)
     return () => {
@@ -116,14 +107,15 @@ export function GardenEditorPage() {
   }, [focusedObjectId, objects, full.data, setFocusedObject])
 
   // Selecting anything lands you in the inspector without a click — the rail
-  // must never be something you operate before you can edit. Deselecting drops
-  // back out of the inspector, but leaves History/Chat open if that's where you
-  // were, since those aren't about the selection.
-  const hasSelection = selectedId != null || selectedPlantingId != null
+  // must never be something you operate before you can edit. Keyed off the
+  // selected ids rather than a "something is selected" boolean, so selecting a
+  // DIFFERENT object while History is open still brings the inspector forward.
+  // Deselecting drops back out of the inspector but leaves History/Chat open if
+  // that's where you were, since those aren't about the selection.
   useEffect(() => {
-    if (hasSelection) setRailTab('inspector')
+    if (selectedId != null || selectedPlantingId != null) setRailTab('inspector')
     else if (useEditorStore.getState().railTab === 'inspector') setRailTab(null)
-  }, [hasSelection, setRailTab])
+  }, [selectedId, selectedPlantingId, setRailTab])
 
   const exitFocus = () => {
     setFocusedObject(null)
@@ -405,9 +397,13 @@ export function GardenEditorPage() {
           activeId={railTab}
           onActivate={setRailTab}
           onClose={() => {
+            // Only the inspector is *about* the selection, so only closing it
+            // deselects; dismissing History leaves the canvas as you had it.
+            if (railTab === 'inspector') {
+              select(null)
+              selectPlanting(null)
+            }
             setRailTab(null)
-            select(null)
-            selectPlanting(null)
           }}
         />
       )}