diff --git a/src/renderers/EventRenderer.ts b/src/renderers/EventRenderer.ts
index 7870e92..45b935f 100644
--- a/src/renderers/EventRenderer.ts
+++ b/src/renderers/EventRenderer.ts
@@ -574,13 +574,24 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
       
       eventsLayer.appendChild(groupContainer);
     } else if (overlapType === OverlapType.STACKING) {
-      // Handle stacking - sort by duration and stack shorter events on top
-      const sortedEvents = [...overlappingEvents].sort((a, b) => {
+      // CRITICAL FIX: Respect existing event position - they stay as base
+      
+      // Separate existing events from the dropped event
+      const existingInOverlap = overlappingEvents.filter(e => e.id !== droppedEvent.id);
+      const droppedIsInList = overlappingEvents.find(e => e.id === droppedEvent.id);
+      
+      // Sort ONLY existing events by duration (among themselves)
+      const sortedExisting = [...existingInOverlap].sort((a, b) => {
         const durationA = new Date(a.end).getTime() - new Date(a.start).getTime();
         const durationB = new Date(b.end).getTime() - new Date(b.start).getTime();
-        return durationB - durationA; // Longer duration first (background)
+        return durationB - durationA; // Longer existing first
       });
       
+      // FINAL ORDER: Existing events first (base), dropped event LAST (stacked on top)
+      const finalEventOrder = droppedIsInList 
+        ? [...sortedExisting, droppedEvent]
+        : sortedExisting;
+      
       // Remove overlapping events from DOM
       const overlappingEventIds = new Set(overlappingEvents.map(e => e.id));
       existingEvents
@@ -590,16 +601,16 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
       
       let underlyingElement: HTMLElement | null = null;
       
-      sortedEvents.forEach((event, index) => {
+      finalEventOrder.forEach((event, index) => {
         const eventElement = this.createEventElement(event);
         this.positionEvent(eventElement, event);
         
         if (index === 0) {
-          // First (longest duration) event renders normally at full width
+          // First event (existing) - always remains base position
           eventsLayer.appendChild(eventElement);
           underlyingElement = eventElement;
         } else {
-          // Shorter events are stacked with margin-left offset and higher z-index
+          // Subsequent events (including dropped) - stacked on top
           if (underlyingElement) {
             this.overlapManager.createStackedEvent(eventElement, underlyingElement, index);
           }