diff --git a/content/treestyletab/bookmarksOverlay.js b/content/treestyletab/bookmarksOverlay.js
index 4178687a..03b803df 100644
--- a/content/treestyletab/bookmarksOverlay.js
+++ b/content/treestyletab/bookmarksOverlay.js
@@ -90,9 +90,17 @@ var TreeStyleTabBookmarksService = {
  
 	getTreeStructureFromItems : function(aIDs) 
 	{
+		/* this returns...
+		  [A]     => -1 (parent is not in this tree)
+		    [B]   => 0 (parent is 1st item in this tree)
+		    [C]   => 0 (parent is 1st item in this tree)
+		      [D] => 2 (parent is 2nd in this tree)
+		  [E]     => -1 (parent is not in this tree, and this creates another tree)
+		    [F]   => 0 (parent is 1st item in this another tree)
+		*/
 		var treeStructure = aIDs.map(function(aId, aIndex) {
 				let id = this.getParentItem(aId);
-				let index = id < 0 ? -1 : aIDs.indexOf(id);
+				let index = aIDs.indexOf(id);
 				return index < aIndex ? index : -1 ;
 			}, this);
 
@@ -116,8 +124,17 @@ var TreeStyleTabBookmarksService = {
 			});
 		treeStructure = treeStructure.reverse();
 
-		treeStructure = treeStructure.map(function(aPosition, aIndex) {
+		var offset = 0;
+		treeStructure = treeStructure
+			.map(function(aPosition, aIndex) {
 				return (aPosition == aIndex) ? -1 : aPosition ;
+			})
+			.map(function(aPosition, aIndex) {
+				if (aPosition == -1) {
+					offset = aIndex;
+					return aPosition;
+				}
+				return aPosition - offset;
 			});
 		return treeStructure;
 	},
diff --git a/content/treestyletab/treestyletabbrowser.js b/content/treestyletab/treestyletabbrowser.js
index fe360f10..75ea9a39 100644
--- a/content/treestyletab/treestyletabbrowser.js
+++ b/content/treestyletab/treestyletabbrowser.js
@@ -1400,13 +1400,17 @@ TreeStyleTabBrowser.prototype = {
 		this.initTab(tab);
 
 		var hasStructure = this.treeStructure && this.treeStructure.length;
-		var positionInTree = hasStructure ? this.treeStructure.shift() : -1 ;
+		var pareintIndexInTree = hasStructure ? this.treeStructure.shift() : 0 ;
 
 		if (this.readiedToAttachNewTab) {
+			if (pareintIndexInTree < 0) { // there is no parent, so this is a new parent!
+				this.parentTab = tab.getAttribute(this.kID);
+			}
+
 			let parent = this.getTabById(this.parentTab);
 			if (parent) {
 				let tabs = [parent].concat(this.getDescendantTabs(parent));
-				parent = (positionInTree > -1 && positionInTree < tabs.length) ? tabs[positionInTree] : parent ;
+				parent = pareintIndexInTree < tabs.length ? tabs[pareintIndexInTree] : parent ;
 			}
 			if (parent) {
 				this.attachTabTo(tab, parent);