diff --git a/modules/tabbarDNDObserver.js b/modules/tabbarDNDObserver.js
index 5f311535..21e66b77 100644
--- a/modules/tabbarDNDObserver.js
+++ b/modules/tabbarDNDObserver.js
@@ -853,12 +853,11 @@ try{
 			}
 		}
 
-		this.clearDropPosition();
-
 		if (
 			!info.canDrop ||
 			observer._setEffectAllowedForDataTransfer(aEvent) == 'none'
 			) {
+			this.clearDropPosition();
 			aEvent.dataTransfer.effectAllowed = "none";
 			return true;
 		}
@@ -870,12 +869,16 @@ try{
 			if (tab) indicatorTab = tab;
 		}
 
-		indicatorTab.setAttribute(
-			sv.kDROP_POSITION,
-			info.position == sv.kDROP_BEFORE ? 'before' :
+		let dropPos = info.position == sv.kDROP_BEFORE ? 'before' :
+
+
 			info.position == sv.kDROP_AFTER ? 'after' :
-			'self'
-		);
+			'self';
+		if (indicatorTab.getAttribute(sv.kDROP_POSITION) != dropPos) {
+			this.clearDropPosition();
+			indicatorTab.setAttribute(sv.kDROP_POSITION, dropPos);
+		}
+
 
 		var indicator = b.mTabDropIndicatorBar || b.tabContainer._tabDropIndicator;
 		indicator.setAttribute('dragging', (info.position == sv.kDROP_ON || sv.isVertical) ? 'false' : 'true' );