diff --git a/src/managers/AllDayManager.ts b/src/managers/AllDayManager.ts
index 1452b55..6cee9cf 100644
--- a/src/managers/AllDayManager.ts
+++ b/src/managers/AllDayManager.ts
@@ -165,8 +165,8 @@ export class AllDayManager {
     eventBus.on('header:ready', async (event: Event) => {
       let headerReadyEventPayload = (event as CustomEvent<IHeaderReadyEventPayload>).detail;
 
-      let startDate = new Date(headerReadyEventPayload.headerElements.at(0)!.data as Date);
-      let endDate = new Date(headerReadyEventPayload.headerElements.at(-1)!.data as Date);
+      let startDate = this.dateService.parseISO(headerReadyEventPayload.headerElements.at(0)!.identifier);
+      let endDate = this.dateService.parseISO(headerReadyEventPayload.headerElements.at(-1)!.identifier);
 
       let events: ICalendarEvent[] = await this.eventManager.getEventsForPeriod(startDate, endDate);
       // Filter for all-day events
@@ -398,7 +398,7 @@ export class AllDayManager {
     this.currentWeekDates = dayHeaders;
 
     // Initialize layout engine with provided week dates
-    let layoutEngine = new AllDayLayoutEngine(dayHeaders.map(column => column.data as Date));
+    let layoutEngine = new AllDayLayoutEngine(dayHeaders.map(column => column.identifier));
 
     // Calculate layout for all events together - AllDayLayoutEngine handles CalendarEvents directly
     return layoutEngine.calculateLayout(events);
@@ -489,8 +489,8 @@ export class AllDayManager {
 
     const clone = dragEndEvent.draggedClone as SwpAllDayEventElement;
     const eventId = clone.eventId.replace('clone-', '');
-    const targetDate = dragEndEvent.finalPosition.column.data as Date;
-    
+    const targetDate = this.dateService.parseISO(dragEndEvent.finalPosition.column.identifier);
+
     console.log('🔄 AllDayManager: Converting timed event to all-day', { eventId, targetDate });
     
     // Create new dates preserving time
@@ -537,8 +537,8 @@ export class AllDayManager {
 
     const clone = dragEndEvent.draggedClone as SwpAllDayEventElement;
     const eventId = clone.eventId.replace('clone-', '');
-    const targetDate = dragEndEvent.finalPosition.column.data as Date;
-    
+    const targetDate = this.dateService.parseISO(dragEndEvent.finalPosition.column.identifier);
+
     // Calculate duration in days
     const durationDays = this.dateService.differenceInCalendarDays(clone.end, clone.start);
     
diff --git a/src/renderers/EventRenderer.ts b/src/renderers/EventRenderer.ts
index a55d0c4..045ffc6 100644
--- a/src/renderers/EventRenderer.ts
+++ b/src/renderers/EventRenderer.ts
@@ -102,7 +102,7 @@ export class DateEventRenderer implements IEventRenderer {
   public handleDragMove(payload: IDragMoveEventPayload): void {
 
     const swpEvent = payload.draggedClone as SwpEventElement;
-    const columnDate = this.dateService.parseISO(payload.columnBounds!!.data as Date);
+    const columnDate = this.dateService.parseISO(payload.columnBounds!!.identifier);
     swpEvent.updatePosition(columnDate, payload.snappedY);
   }
 
@@ -118,7 +118,7 @@ export class DateEventRenderer implements IEventRenderer {
       // Recalculate timestamps with new column date
       const currentTop = parseFloat(payload.draggedClone.style.top) || 0;
       const swpEvent = payload.draggedClone as SwpEventElement;
-      const columnDate = this.dateService.parseISO(payload.newColumn.data as Date);
+      const columnDate = this.dateService.parseISO(payload.newColumn.identifier);
       swpEvent.updatePosition(columnDate, currentTop);
     }
   }
@@ -130,7 +130,7 @@ export class DateEventRenderer implements IEventRenderer {
 
     console.log('🎯 DateEventRenderer: Converting all-day to timed event', {
       eventId: payload.calendarEvent.id,
-      targetColumn: payload.targetColumn.data as Date,
+      targetColumn: payload.targetColumn.identifier,
       snappedY: payload.snappedY
     });
 
diff --git a/src/renderers/EventRendererManager.ts b/src/renderers/EventRendererManager.ts
index 31ac768..7d2f0fd 100644
--- a/src/renderers/EventRendererManager.ts
+++ b/src/renderers/EventRendererManager.ts
@@ -216,7 +216,7 @@ export class EventRenderingService {
                 cloneElement.style.display = '';
 
             console.log('🚪 EventRendererManager: Received drag:mouseleave-header', {
-                targetDate,
+                targetColumn: targetColumn?.identifier,
                 originalElement: originalElement,
                 cloneElement: cloneElement
             });
@@ -296,7 +296,7 @@ export class EventRenderingService {
         }
 
         // Re-render target column if exists and different from source
-        if (targetColumn && (targetColumn.data as Date) !== (originalSourceColumn?.data as Date)) {
+        if (targetColumn && targetColumn.identifier !== originalSourceColumn?.identifier) {
             await this.renderSingleColumn(targetColumn);
         }
     }
@@ -317,7 +317,7 @@ export class EventRenderingService {
      */
     private async renderSingleColumn(column: IColumnBounds): Promise<void> {
         // Get events for just this column's date
-        const dateString = (column.data as Date).toISOString().split('T')[0];
+        const dateString = column.identifier;
         const columnStart = this.dateService.parseISO(`${dateString}T00:00:00`);
         const columnEnd = this.dateService.parseISO(`${dateString}T23:59:59.999`);
 
@@ -343,7 +343,7 @@ export class EventRenderingService {
         }
 
         console.log('🔄 EventRendererManager: Re-rendered single column', {
-            columnDate: column.data as Date,
+            columnDate: column.identifier,
             eventsCount: timedEvents.length
         });
     }