--- a/browser/base/content/tabview/drag.js
+++ b/browser/base/content/tabview/drag.js
@@ -96,25 +96,26 @@ function Drag(item, event, isResizing, i
 
 Drag.prototype = {
   // ----------
   // Function: snapBounds
   // Adjusts the given bounds according to the currently active trenches. Used by <Drag.snap>
   //
   // Parameters:
   //   bounds             - (<Rect>) bounds
-  //   stationaryCorner   - which corner is stationary? by default, the top left.
+  //   stationaryCorner   - which corner is stationary? by default, the top left in LTR mode,
+  //                        and top right in RTL mode.
   //                        "topleft", "bottomleft", "topright", "bottomright"
   //   assumeConstantSize - (boolean) whether the bounds' dimensions are sacred or not.
   //   keepProportional   - (boolean) if assumeConstantSize is false, whether we should resize
   //                        proportionally or not
   //   checkItemStatus    - (boolean) make sure this is a valid item which should be snapped
   snapBounds: function Drag_snapBounds(bounds, stationaryCorner, assumeConstantSize, keepProportional, checkItemStatus) {
     if (!stationaryCorner)
-      stationaryCorner = 'topleft';
+      stationaryCorner = UI.rtl ? 'topright' : 'topleft';
     var update = false; // need to update
     var updateX = false;
     var updateY = false;
     var newRect;
     var snappedTrenches = {};
 
     // OH SNAP!
 
@@ -159,17 +160,18 @@ Drag.prototype = {
 
   // ----------
   // Function: snap
   // Called when a drag or mousemove occurs. Set the bounds based on the mouse move first, then
   // call snap and it will adjust the item's bounds if appropriate. Also triggers the display of
   // trenches that it snapped to.
   //
   // Parameters:
-  //   stationaryCorner   - which corner is stationary? by default, the top left.
+  //   stationaryCorner   - which corner is stationary? by default, the top left in LTR mode,
+  //                        and top right in RTL mode.
   //                        "topleft", "bottomleft", "topright", "bottomright"
   //   assumeConstantSize - (boolean) whether the bounds' dimensions are sacred or not.
   //   keepProportional   - (boolean) if assumeConstantSize is false, whether we should resize
   //                        proportionally or not
   snap: function Drag_snap(stationaryCorner, assumeConstantSize, keepProportional) {
     var bounds = this.item.getBounds();
     bounds = this.snapBounds(bounds, stationaryCorner, assumeConstantSize, keepProportional, true);
     if (bounds) {
@@ -182,17 +184,18 @@ Drag.prototype = {
   // --------
   // Function: snapToEdge
   // Returns a version of the bounds snapped to the edge if it is close enough. If not,
   // returns false. If <Keys.meta> is true, this function will simply enforce the
   // window edges.
   //
   // Parameters:
   //   rect - (<Rect>) current bounds of the object
-  //   stationaryCorner   - which corner is stationary? by default, the top left.
+  //   stationaryCorner   - which corner is stationary? by default, the top left in LTR mode,
+  //                        and top right in RTL mode.
   //                        "topleft", "bottomleft", "topright", "bottomright"
   //   assumeConstantSize - (boolean) whether the rect's dimensions are sacred or not
   //   keepProportional   - (boolean) if we are allowed to change the rect's size, whether the
   //                                  dimensions should scaled proportionally or not.
   snapToEdge: function Drag_snapToEdge(rect, stationaryCorner, assumeConstantSize, keepProportional) {
 
     var swb = this.safeWindowBounds;
     var update = false;
@@ -253,17 +256,17 @@ Drag.prototype = {
     }
     return false;
   },
 
   // ----------
   // Function: drag
   // Called in response to an <Item> draggable "drag" event.
   drag: function Drag_drag(event) {
-    this.snap('topleft', true);
+    this.snap(UI.rtl ? 'topright' : 'topleft', true);
 
     if (this.parent && this.parent.expanded) {
       var distance = this.startPosition.distance(new Point(event.clientX, event.clientY));
       if (distance > 100) {
         this.parent.remove(this.item);
         this.parent.collapse();
       }
     }

--- a/browser/base/content/tabview/groupitems.js
+++ b/browser/base/content/tabview/groupitems.js
@@ -451,18 +451,18 @@ GroupItem.prototype = Utils.extend(new I
     if (!Utils.isRect(rect)) {
       Utils.trace('GroupItem.setBounds: rect is not a real rectangle!', rect);
       return;
     }
 
     if (!options)
       options = {};
 
-    rect.width = Math.max(110, rect.width);
-    rect.height = Math.max(125, rect.height);
+    rect.width = Math.max(90, rect.width);
+    rect.height = Math.max(90, rect.height);
 
     var titleHeight = this.$titlebar.height();
 
     // ___ Determine what has changed
     var css = {};
     var titlebarCSS = {};
     var contentCSS = {};
 

--- a/browser/base/content/tabview/items.js
+++ b/browser/base/content/tabview/items.js
@@ -222,18 +222,17 @@ Item.prototype = {
       minWidth: 90,
       minHeight: 90,
       start: function(e,ui) {
         if (this.isAGroupItem)
           GroupItems.setActiveGroupItem(this);
         resizeInfo = new Drag(this, e, true); // true = isResizing
       },
       resize: function(e,ui) {
-        // TODO: maybe the stationaryCorner should be topright for rtl langs?
-        resizeInfo.snap('topleft', false, self.keepProportional);
+        resizeInfo.snap(UI.rtl ? 'topright' : 'topleft', false, self.keepProportional);
       },
       stop: function() {
         self.setUserSize();
         self.pushAway();
         resizeInfo.stop();
         resizeInfo = null;
       }
     };
@@ -764,17 +763,26 @@ Item.prototype = {
         var self = this;
         var startMouse;
         var startSize;
 
         // ___ mousemove
         var handleMouseMove = function(e) {
           var mouse = new Point(e.pageX, e.pageY);
           var box = self.getBounds();
-          box.width = Math.max(self.resizeOptions.minWidth || 0, startSize.x + (mouse.x - startMouse.x));
+          if (UI.rtl) {
+            var minWidth = (self.resizeOptions.minWidth || 0);
+            var oldWidth = box.width;
+            if (minWidth != oldWidth || mouse.x < startMouse.x) {
+              box.width = Math.max(minWidth, startSize.x - (mouse.x - startMouse.x));
+              box.left -= box.width - oldWidth;
+            }
+          } else {
+            box.width = Math.max(self.resizeOptions.minWidth || 0, startSize.x + (mouse.x - startMouse.x));
+          }
           box.height = Math.max(self.resizeOptions.minHeight || 0, startSize.y + (mouse.y - startMouse.y));
 
           if (self.resizeOptions.aspectRatio) {
             if (startAspect < 1)
               box.height = box.width * startAspect;
             else
               box.width = box.height / startAspect;
           }

--- a/browser/base/content/tabview/trench.js
+++ b/browser/base/content/tabview/trench.js
@@ -472,17 +472,17 @@ var Trenches = {
   defaultRadius: 10,
   disabled: false,
 
   // ---------
   // Variables: snapping preferences; used to break ties in snapping.
   //   preferTop - (boolean) prefer snapping to the top to the bottom
   //   preferLeft - (boolean) prefer snapping to the left to the right
   preferTop: true,
-  preferLeft: true,
+  get preferLeft() { return !UI.rtl; },
 
   trenches: [],
 
   // ---------
   // Function: getById
   // Return the specified <Trench>.
   //
   // Parameters: