diff --git a/frontend/js/pane-manager.js b/frontend/js/pane-manager.js
index 3a70153..561a5fc 100644
--- a/frontend/js/pane-manager.js
+++ b/frontend/js/pane-manager.js
@@ -366,11 +366,14 @@ function createPaneTabManager(paneId) {
           this._showTabContextMenu(e.clientX, e.clientY, tab.id);
         });
 
-        // Drag within same pane
+        // Drag within same pane (+ cross-pane via container drop zone)
         el.addEventListener('dragstart', (e) => {
-          e.dataTransfer.setData('application/obsigate-tab', JSON.stringify({
+          const payload = JSON.stringify({
             paneId: this.paneId, tabId: tab.id, index: idx
-          }));
+          });
+          e.dataTransfer.setData('application/obsigate-tab', payload);
+          e.dataTransfer.setData('text/plain', payload); // fallback for browser compat
+          e.dataTransfer.effectAllowed = 'move';
           el.classList.add('dragging');
         });
         el.addEventListener('dragend', () => {
@@ -737,16 +740,12 @@ const PaneManager = {
     let _dragCounter = 0;
 
     container.addEventListener('dragenter', (e) => {
-      const types = Array.from(e.dataTransfer.types || []);
-      if (!types.includes('application/obsigate-tab')) return;
       _dragCounter++;
-      e.preventDefault();
+      e.preventDefault(); // Accept the drop unconditionally
     });
 
     container.addEventListener('dragover', (e) => {
-      const types = Array.from(e.dataTransfer.types || []);
-      if (!types.includes('application/obsigate-tab')) return;
-      e.preventDefault();
+      e.preventDefault(); // Required for drop to work
       e.dataTransfer.dropEffect = 'move';
 
       // Detect edge zones for drag-to-split (only in single-pane mode)
@@ -776,7 +775,7 @@ const PaneManager = {
 
     container.addEventListener('dragleave', (e) => {
       _dragCounter--;
-      if (_dragCounter > 0) return; // Still inside container (entered a child)
+      if (_dragCounter > 0) return;
       container.querySelectorAll('.pane-drop-zone-indicator').forEach(d => d.remove());
       const tabBar = container.querySelector('.tab-bar');
       if (tabBar) tabBar.classList.remove('drop-target');
@@ -790,11 +789,15 @@ const PaneManager = {
       const tabBar = container.querySelector('.tab-bar');
       if (tabBar) tabBar.classList.remove('drop-target');
 
-      const raw = e.dataTransfer.getData('application/obsigate-tab');
+      // Try both data formats
+      let raw = e.dataTransfer.getData('application/obsigate-tab');
+      if (!raw) raw = e.dataTransfer.getData('text/plain');
       if (!raw) return;
+
       try {
         const dragData = JSON.parse(raw);
-        if (dragData.paneId === paneId) return; // Same pane, let tab handler deal with it
+        if (dragData.paneId == null || dragData.tabId == null) return;
+        if (dragData.paneId === paneId) return; // Same pane, tab handler deals with it
 
         // Recalculate edge zone from drop coordinates
         const rect = container.getBoundingClientRect();
@@ -803,24 +806,21 @@ const PaneManager = {
         const isSingle = !this.isSplit();
 
         if (isSingle && relX > rect.width * 0.72) {
-          // Dropped on right edge → split right with this tab
           this.splitRight();
           setTimeout(() => {
             const newPaneId = this.panes.length - 1;
             this.transferTab(dragData.paneId, dragData.tabId, newPaneId);
-          }, 150);
+          }, 200);
         } else if (isSingle && relY > rect.height * 0.72) {
-          // Dropped on bottom edge → split down with this tab
           this.splitDown();
           setTimeout(() => {
             const newPaneId = this.panes.length - 1;
             this.transferTab(dragData.paneId, dragData.tabId, newPaneId);
-          }, 150);
+          }, 200);
         } else {
-          // Cross-pane transfer (dropped on tab bar or empty area of another pane)
           this.transferTab(dragData.paneId, dragData.tabId, paneId);
         }
-      } catch (e2) { /* ignore */ }
+      } catch (e2) { console.debug('PaneManager drop error:', e2); }
     });
   },