Improves event drag and drop stack handling

Addresses an issue where dragging events that are part of a stack could lead to inconsistencies.

This change ensures that when an event is dragged and dropped, the other events in the stack are also repositioned correctly.
It traverses the stack, removes the related events from their original positions, and re-renders them in the correct column.
It also removes stack link data from the dragged element to prevent unexpected behavior.

src/renderers/EventRenderer.ts

@@ -372,6 +372,79 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
       return;
     }
     
+    // Check om original event var del af en stack
+    const originalStackLink = this.originalEvent.dataset.stackLink;
+
+    if (originalStackLink) {
+      try {
+        const stackData = JSON.parse(originalStackLink);
+        const stackEventIds: string[] = [];
+        
+        // Saml ALLE event IDs fra hele stack chain
+        const allStackEventIds: Set<string> = new Set();
+
+        // Recursive funktion til at traversere stack chain
+        const traverseStack = (linkData: any, visitedIds: Set<string>) => {
+          if (linkData.prev && !visitedIds.has(linkData.prev)) {
+            visitedIds.add(linkData.prev);
+            const prevElement = document.querySelector(`swp-time-grid [data-event-id="${linkData.prev}"]`) as HTMLElement;
+            if (prevElement?.dataset.stackLink) {
+              try {
+                const prevLinkData = JSON.parse(prevElement.dataset.stackLink);
+                traverseStack(prevLinkData, visitedIds);
+              } catch (e) {}
+            }
+          }
+          
+          if (linkData.next && !visitedIds.has(linkData.next)) {
+            visitedIds.add(linkData.next);
+            const nextElement = document.querySelector(`swp-time-grid [data-event-id="${linkData.next}"]`) as HTMLElement;
+            if (nextElement?.dataset.stackLink) {
+              try {
+                const nextLinkData = JSON.parse(nextElement.dataset.stackLink);
+                traverseStack(nextLinkData, visitedIds);
+              } catch (e) {}
+            }
+          }
+        };
+
+        // Start traversering fra original event's stackLink
+        traverseStack(stackData, allStackEventIds);
+
+        // Fjern original eventId da det bliver flyttet
+        allStackEventIds.delete(eventId);
+
+        // Find alle stack events og fjern dem
+        const stackEvents: CalendarEvent[] = [];
+        let container: HTMLElement | null = null;
+
+        allStackEventIds.forEach(id => {
+          const element = document.querySelector(`swp-time-grid [data-event-id="${id}"]`) as HTMLElement;
+          if (element) {
+            // Gem container reference fra første element
+            if (!container) {
+              container = element.closest('swp-events-layer') as HTMLElement;
+            }
+            
+            const event = this.elementToCalendarEvent(element);
+            if (event) {
+              stackEvents.push(event);
+            }
+            
+            // Fjern elementet
+            element.remove();
+          }
+        });
+        
+        // Re-render stack events hvis vi fandt nogle
+        if (stackEvents.length > 0 && container) {
+          this.new_handleEventOverlaps(stackEvents, container);
+        }
+      } catch (e) {
+        console.warn('Failed to parse stackLink data:', e);
+      }
+    }
+    
     // Remove original event from any existing groups first
     this.removeEventFromExistingGroups(this.originalEvent);
     
@@ -399,6 +472,12 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     
     // Detect overlaps with other events in the target column and reposition if needed
     this.handleDragDropOverlaps(this.draggedClone, finalColumn);
+    
+    // Fjern stackLink data fra dropped element
+    if (this.draggedClone.dataset.stackLink) {
+      delete this.draggedClone.dataset.stackLink;
+    }
+    
     // Clean up
     this.draggedClone = null;
     this.originalEvent = null;
@@ -1273,6 +1352,13 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
       
       const element = this.renderEvent(event);
       
+      // Gem stack link information på DOM elementet
+      element.dataset.stackLink = JSON.stringify({
+        prev: stackLink.prev,
+        next: stackLink.next,
+        stackLevel: stackLink.stackLevel
+      });
+      
       // Check om dette event deler kolonne med foregående (samme start tid)
       if (stackLink.prev) {
         const prevEvent = result.overlappingEvents.find(e => e.id === stackLink.prev);