fix: calendar click/double-click created events near current time instead of the clicked slot

components/calendar/calendar-app.tsx

@@ -1664,11 +1664,16 @@ export function CalendarApp({ linkSegments }: CalendarAppProps = {}) {
               const d = new Date(date);
               if (typeof hour === "number") {
                 d.setHours(hour, 0, 0, 0);
+                // Explicit end so the modal keeps the clicked hour instead of
+                // applying its next-hour fallback for date-only defaults (#435).
+                const end = new Date(date);
+                end.setHours(hour + 1, 0, 0, 0);
+                openCreateModal(d, end);
               } else {
                 const now = new Date();
                 d.setHours(now.getHours() + 1, 0, 0, 0);
+                openCreateModal(d);
               }
-              openCreateModal(d);
             }}
             onNewAllDayEvent={() => {
               const d = new Date(date);

hooks/__tests__/use-time-grid-interactions.test.ts

@@ -0,0 +1,66 @@
+import { act, renderHook } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { useTimeGridInteractions } from "@/hooks/use-time-grid-interactions";
+
+const errorMessages = { resize: "resize", move: "move", created: "created", error: "error" };
+
+function renderInteractions(onCreateRange = vi.fn()) {
+  const { result } = renderHook(() =>
+    useTimeGridInteractions({ hourHeight: 60, calendars: [], onCreateRange, errorMessages }),
+  );
+  return { result, onCreateRange };
+}
+
+describe("useTimeGridInteractions slot clicks (#435)", () => {
+  beforeEach(() => {
+    // Freeze "now" far from the clicked slot so a regression to the modal's
+    // next-hour-from-now fallback would produce a different time than asserted.
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date(2026, 7, 21, 12, 2, 0));
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it("single click creates a range at the clicked hour, not near the current time", () => {
+    const { result, onCreateRange } = renderInteractions();
+    const day = new Date(2026, 8, 3);
+
+    act(() => result.current.handleSlotClick(day, 16));
+    act(() => vi.advanceTimersByTime(300));
+
+    expect(onCreateRange).toHaveBeenCalledTimes(1);
+    const [start, end] = onCreateRange.mock.calls[0];
+    expect(start).toEqual(new Date(2026, 8, 3, 16, 0, 0, 0));
+    expect(end).toEqual(new Date(2026, 8, 3, 17, 0, 0, 0));
+  });
+
+  it("double click creates a range at the clicked hour immediately", () => {
+    const { result, onCreateRange } = renderInteractions();
+    const day = new Date(2026, 8, 3);
+
+    act(() => result.current.handleSlotClick(day, 9));
+    act(() => result.current.handleSlotDoubleClick(day, 9));
+
+    expect(onCreateRange).toHaveBeenCalledTimes(1);
+    const [start, end] = onCreateRange.mock.calls[0];
+    expect(start).toEqual(new Date(2026, 8, 3, 9, 0, 0, 0));
+    expect(end).toEqual(new Date(2026, 8, 3, 10, 0, 0, 0));
+
+    // The pending single-click timer must have been cancelled by the double click.
+    act(() => vi.advanceTimersByTime(500));
+    expect(onCreateRange).toHaveBeenCalledTimes(1);
+  });
+
+  it("a 23:00 click ends at midnight of the next day", () => {
+    const { result, onCreateRange } = renderInteractions();
+    const day = new Date(2026, 8, 3);
+
+    act(() => result.current.handleSlotDoubleClick(day, 23));
+
+    const [start, end] = onCreateRange.mock.calls[0];
+    expect(start).toEqual(new Date(2026, 8, 3, 23, 0, 0, 0));
+    expect(end).toEqual(new Date(2026, 8, 4, 0, 0, 0, 0));
+  });
+});

hooks/use-time-grid-interactions.ts

@@ -256,6 +256,18 @@ export function useTimeGridInteractions({
   const clickTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const [quickCreate, setQuickCreate] = useState<QuickCreateState | null>(null);
 
+  // Pass an explicit end alongside the clicked slot: the event modal only
+  // honors a timed `defaultDate` when `defaultEndDate` is present — without it
+  // the modal falls back to "next hour from now" (meant for date-only month
+  // clicks) and discards the clicked time (#435).
+  const slotToRange = useCallback((day: Date, hour: number): [Date, Date] => {
+    const start = new Date(day);
+    start.setHours(hour, 0, 0, 0);
+    const end = new Date(day);
+    end.setHours(hour + 1, 0, 0, 0);
+    return [start, end];
+  }, []);
+
   const handleSlotClick = useCallback((day: Date, hour: number) => {
     if (wasDragging.current) return;
     if (clickTimerRef.current) {
@@ -265,11 +277,9 @@ export function useTimeGridInteractions({
     }
     clickTimerRef.current = setTimeout(() => {
       clickTimerRef.current = null;
-      const d = new Date(day);
-      d.setHours(hour, 0, 0, 0);
-      onCreateRange(d);
+      onCreateRange(...slotToRange(day, hour));
     }, 250);
-  }, [onCreateRange]);
+  }, [onCreateRange, slotToRange]);
 
   const handleSlotDoubleClick = useCallback((day: Date, hour: number) => {
     if (wasDragging.current) return;
@@ -277,10 +287,8 @@ export function useTimeGridInteractions({
       clearTimeout(clickTimerRef.current);
       clickTimerRef.current = null;
     }
-    const d = new Date(day);
-    d.setHours(hour, 0, 0, 0);
-    onCreateRange(d);
-  }, [onCreateRange]);
+    onCreateRange(...slotToRange(day, hour));
+  }, [onCreateRange, slotToRange]);
 
   const handleQuickCreateSubmit = useCallback(async (title: string) => {
     if (!quickCreate) return;