diff --git a/content/treestyletab/treestyletab.js b/content/treestyletab/treestyletab.js
index 6a9ce5b2..0a72ad92 100644
--- a/content/treestyletab/treestyletab.js
+++ b/content/treestyletab/treestyletab.js
@@ -1209,6 +1209,18 @@ catch(e) {
 		if (!this.getTreePref('enableSubtreeIndent.allTabsPopup')) return;
 
 		var items = Array.slice(aEvent.originalTarget.childNodes);
+		var firstItemIndex = 0;
+		// ignore menu items inserted by Weave
+		if (items.some(function(aItem, aIndex) {
+				if ((aItem.getAttribute('anonid') || aItem.id) == 'sync-tabs-sep') {
+					firstItemIndex = aIndex + 1;
+					return true;
+				}
+				return false;
+			})) {
+			items = items.slice(firstItemIndex);
+		}
+
 		var b = this.getTabBrowserFromChild(aEvent.originalTarget) || gBrowser;
 		this.getTabsArray(b).forEach(function(aTab, aIndex) {
 			items[aIndex].style.paddingLeft = aTab.getAttribute(this.kNEST)+'em';