diff --git a/src/renderers/EventRenderer.ts b/src/renderers/EventRenderer.ts
index add09fb..1e2475d 100644
--- a/src/renderers/EventRenderer.ts
+++ b/src/renderers/EventRenderer.ts
@@ -63,6 +63,84 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
       const { eventId, targetDate, headerRenderer } = (event as CustomEvent).detail;
       this.handleConvertToAllDay(eventId, targetDate, headerRenderer);
     });
+    
+    // Listen for header mouseover events (like original ColumnDetector)
+    eventBus.on('header:mouseover', (event) => {
+      const { element, targetDate, headerRenderer } = (event as CustomEvent).detail;
+      
+      if (this.draggedClone && targetDate) {
+        // Scenario 1: Timed event being dragged to header - convert to all-day
+        if (this.draggedClone.tagName === 'SWP-EVENT') {
+          console.log('EventRenderer: Converting timed event to all-day for date:', targetDate);
+          headerRenderer.addToAllDay(element);
+          this.convertToAllDayPreview(targetDate);
+        }
+        
+        // Scenario 2: All-day event being moved to different day
+        else if (this.draggedClone.tagName === 'SWP-ALLDAY-EVENT') {
+          const currentDate = this.draggedClone.parentElement?.getAttribute('data-date');
+          if (currentDate !== targetDate) {
+            console.log('EventRenderer: Moving all-day event from', currentDate, 'to', targetDate);
+            this.moveAllDayToNewDate(targetDate);
+          }
+        }
+      }
+    });
+    
+    // Setup header mouseover detection for all-day conversion
+    this.setupHeaderMouseoverDetection();
+  }
+  
+  /**
+   * Setup header mouseover detection during drag
+   */
+  private setupHeaderMouseoverDetection(): void {
+    document.addEventListener('mouseover', (event) => {
+      if (!this.draggedClone) return; // Only during active drag
+      
+      const target = event.target as HTMLElement;
+      
+      // Check if mouse is over a day header
+      let dayHeader = target.closest('swp-day-header') as HTMLElement;
+      if (dayHeader) {
+        const targetDate = dayHeader.dataset.date;
+        if (targetDate && this.draggedClone.tagName === 'SWP-EVENT') {
+          console.log(`EventRenderer: Mouse over day header for date ${targetDate}`);
+          
+          // Find the header renderer from the calendar header
+          const calendarHeader = dayHeader.closest('swp-calendar-header');
+          if (calendarHeader) {
+            // Emit header mouseover event like the original ColumnDetector did
+            eventBus.emit('header:mouseover', {
+              element: dayHeader,
+              targetDate: targetDate,
+              headerRenderer: this.getHeaderRenderer()
+            });
+          }
+        }
+      }
+    });
+  }
+  
+  /**
+   * Get the header renderer instance for triggering addToAllDay
+   */
+  private getHeaderRenderer(): any {
+    // For now, we'll create a simple object with the addToAllDay method
+    // This mimics what ColumnDetector had access to
+    return {
+      addToAllDay: (element: HTMLElement) => {
+        // Find the calendar header and call the HeaderRenderer's addToAllDay method
+        const calendarHeader = element.closest('swp-calendar-header') as HTMLElement;
+        if (calendarHeader) {
+          // Import and use HeaderRenderer directly
+          import('./HeaderRenderer').then(({ BaseHeaderRenderer }) => {
+            const headerRenderer = new BaseHeaderRenderer();
+            headerRenderer.addToAllDay(element);
+          });
+        }
+      }
+    };
   }
   
   /**
@@ -348,6 +426,56 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
       element.remove();
     }, 300);
   }
+  
+  /**
+   * Convert dragged clone to all-day event preview
+   */
+  private convertToAllDayPreview(targetDate: string): void {
+    if (!this.draggedClone) return;
+
+    // Only convert once
+    if (this.draggedClone.tagName === 'SWP-ALLDAY-EVENT') {
+      return;
+    }
+
+    // Transform clone to all-day format
+    this.transformCloneToAllDay(this.draggedClone, targetDate);
+
+    console.log(`EventRenderer: Converted clone to all-day preview for ${targetDate}`);
+  }
+  
+  /**
+   * Move all-day event to a new date container
+   */
+  private moveAllDayToNewDate(targetDate: string): void {
+    if (!this.draggedClone) return;
+    
+    const calendarHeader = document.querySelector('swp-calendar-header');
+    if (!calendarHeader) return;
+    
+    // Find the all-day container
+    const allDayContainer = calendarHeader.querySelector('swp-allday-container');
+    if (!allDayContainer) return;
+    
+    // Calculate new column index
+    const dayHeaders = document.querySelectorAll('swp-day-header');
+    let columnIndex = 1;
+    dayHeaders.forEach((header, index) => {
+      if ((header as HTMLElement).dataset.date === targetDate) {
+        columnIndex = index + 1;
+      }
+    });
+    
+    // Update grid column position
+    (this.draggedClone as HTMLElement).style.gridColumn = columnIndex.toString();
+    
+    // Move to all-day container if not already there
+    if (this.draggedClone.parentElement !== allDayContainer) {
+      allDayContainer.appendChild(this.draggedClone);
+    }
+    
+    console.log(`EventRenderer: Moved all-day event to date ${targetDate}, column ${columnIndex}`);
+  }
   renderEvents(events: CalendarEvent[], container: HTMLElement, config: CalendarConfig): void {
     console.log('BaseEventRenderer: renderEvents called with', events.length, 'events');