diff --git a/src/managers/AllDayManager.ts b/src/managers/AllDayManager.ts
index f601c5a..bf11c70 100644
--- a/src/managers/AllDayManager.ts
+++ b/src/managers/AllDayManager.ts
@@ -127,14 +127,14 @@ export class AllDayManager {
     eventBus.on('header:ready', (event: Event) => {
       let headerReadyEventPayload = (event as CustomEvent<HeaderReadyEventPayload>).detail;
 
-      var startDate = headerReadyEventPayload.headerElements.startDate;
-      var endDate = headerReadyEventPayload.headerElements.endDate;
+      let startDate = new Date(headerReadyEventPayload.headerElements.at(0)!.date);
+      let endDate = new Date(headerReadyEventPayload.headerElements.at(-1)!.date);
 
       var events: CalendarEvent[] = this.eventManager.getEventsForPeriod(startDate, endDate);
       // Filter for all-day events
       const allDayEvents = events.filter(event => event.allDay);
-      
-      var eventLayouts = this.calculateAllDayEventsLayout(allDayEvents, headerReadyEventPayload.headerElements)
+
+      let eventLayouts = this.calculateAllDayEventsLayout(allDayEvents, headerReadyEventPayload.headerElements)
 
       this.allDayEventRenderer.renderAllDayEventsForPeriod(eventLayouts);
       this.checkAndAnimateAllDayHeight();
@@ -304,14 +304,14 @@ export class AllDayManager {
    * Calculate layout for ALL all-day events using AllDayLayoutEngine
    * This is the correct method that processes all events together for proper overlap detection
    */
-  private calculateAllDayEventsLayout(events: CalendarEvent[], weekDates: ColumnBounds[]): EventLayout[] {
+  private calculateAllDayEventsLayout(events: CalendarEvent[], dayHeaders: ColumnBounds[]): EventLayout[] {
 
     // Store current state
     this.currentAllDayEvents = events;
-    this.currentWeekDates = weekDates;
+    this.currentWeekDates = dayHeaders;
 
     // Initialize layout engine with provided week dates
-    var layoutEngine = new AllDayLayoutEngine(weekDates);
+    let layoutEngine = new AllDayLayoutEngine(dayHeaders.map(column => column.date));
 
     // Calculate layout for all events together - AllDayLayoutEngine handles CalendarEvents directly
     return layoutEngine.calculateLayout(events);
diff --git a/src/managers/HeaderManager.ts b/src/managers/HeaderManager.ts
index 77f5bcf..b884979 100644
--- a/src/managers/HeaderManager.ts
+++ b/src/managers/HeaderManager.ts
@@ -5,8 +5,6 @@ import { CoreEvents } from '../constants/CoreEvents';
 import { HeaderRenderContext } from '../renderers/HeaderRenderer';
 import { ResourceCalendarData } from '../types/CalendarTypes';
 import { DragMouseEnterHeaderEventPayload, DragMouseLeaveHeaderEventPayload, HeaderReadyEventPayload } from '../types/EventTypes';
-import { DateCalculator } from '../utils/DateCalculator';
-import { PositionUtils } from '../utils/PositionUtils';
 import { ColumnDetectionUtils } from '../utils/ColumnDetectionUtils';
 
 /**
@@ -138,10 +136,6 @@ export class HeaderManager {
     // Setup event listeners on the new content
     this.setupHeaderDragListeners();
 
-    // Calculate period from current date
-    const weekStart = DateCalculator.getISOWeekStart(currentDate);
-    const weekEnd = DateCalculator.addDays(weekStart, 6);
-    
     // Notify other managers that header is ready with period data
     const payload: HeaderReadyEventPayload = {
       headerElements: ColumnDetectionUtils.getHeaderColumns(),