Preserves event duration during drag and drop

Ensures all-day events maintain their original duration
when dragged and dropped to a new date.

Calculates and applies the correct end date based on the
original event's span.

src/managers/AllDayManager.ts

@@ -343,10 +343,16 @@ export class AllDayManager {
     if (!dragColumnChangeEventPayload.draggedClone)
       return;
 
-    // Update clone position - ALWAYS keep in row 1 during drag
-    // Use simple grid positioning that matches all-day container structure
-    dragColumnChangeEventPayload.draggedClone.style.gridColumn = targetColumn.index.toString();
-    //dragColumnChangeEventPayload.draggedClone.style.gridRow = dragColumnChangeEventPayload.draggedClone.style.gridRow; // Bevar nuværende row
+    // Calculate event span from original grid positioning
+    const computedStyle = window.getComputedStyle(dragColumnChangeEventPayload.draggedClone);
+    const gridColumnStart = parseInt(computedStyle.gridColumnStart) || targetColumn.index;
+    const gridColumnEnd = parseInt(computedStyle.gridColumnEnd) || targetColumn.index + 1;
+    const span = gridColumnEnd - gridColumnStart;
+
+    // Update clone position maintaining the span
+    const newStartColumn = targetColumn.index;
+    const newEndColumn = newStartColumn + span;
+    dragColumnChangeEventPayload.draggedClone.style.gridColumn = `${newStartColumn} / ${newEndColumn}`;
 
   }
   private fadeOutAndRemove(element: HTMLElement): void {
@@ -357,11 +363,25 @@ export class AllDayManager {
       element.remove();
     }, 300);
   }
-  /**
-   * Handle drag end for all-day events - WITH DIFFERENTIAL UPDATES
-   */
+
+
   private handleDragEnd(dragEndEvent: DragEndEventPayload): void {
 
+    const getEventDurationDays = (start: string|undefined, end: string|undefined): number => {
+      
+      if(!start || !end)
+        throw new Error('Undefined start or end - date');
+
+      const startDate = new Date(start);
+      const endDate = new Date(end);
+
+      if (isNaN(startDate.getTime()) || isNaN(endDate.getTime())) {
+        throw new Error('Ugyldig start eller slut-dato i dataset');
+      }
+
+      return Math.round((endDate.getTime() - startDate.getTime()) / (1000 * 60 * 60 * 24));
+    };
+
     if (dragEndEvent.draggedClone == null)
       return;
 
@@ -378,12 +398,21 @@ export class AllDayManager {
       return;
 
 
+    // Calculate original event duration
+  
+
+
+    const durationDays = getEventDurationDays(dragEndEvent.draggedClone.dataset.start, dragEndEvent.draggedClone.dataset.end);
+    const newStartDate = new Date(eventDate);
+    const newEndDate = new Date(newStartDate);
+    newEndDate.setDate(newEndDate.getDate() + durationDays);
+
 
     const droppedEvent: CalendarEvent = {
       id: eventId,
       title: dragEndEvent.draggedClone.dataset.title || '',
-      start: new Date(eventDate),
-      end: new Date(eventDate),
+      start: newStartDate,
+      end: newEndDate,
       type: eventType,
       allDay: true,
       syncStatus: 'synced'