Fix selection in calendar

frontend/src/pages/Calendar.tsx

@@ -184,6 +184,13 @@ export function Calendar(): ReactNode {
   const defaultLeaveType = getLastLeaveType() ?? 'vacation'
   const firstSelectedDate = Array.from(selectedDates).sort()[0]
 
+  // Dates to highlight in the grid. While dragging, show a live preview of the
+  // range under the cursor; otherwise show the committed selection.
+  const highlightedDates =
+    isDragging && dragAnchor && dragCurrent
+      ? new Set(datesInRange(dragAnchor, dragCurrent))
+      : selectedDates
+
   return (
     <Layout>
       <div data-testid="calendar" className="calendar">
@@ -215,7 +222,7 @@ export function Calendar(): ReactNode {
                 key={weekIdx}
                 weekDates={week}
                 plannedDays={plannedDays ?? []}
-                selectedDates={selectedDates}
+                selectedDates={highlightedDates}
                 parentName={parentName ?? 'Du'}
                 personalDataUuid={personalDataUuid ?? ''}
                 isCurrentMonth={weekMonth === month}