diff --git a/node_modules/ace/lib/ace/edit_session.js b/node_modules/ace/lib/ace/edit_session.js
index 81ae0680..7813b3d0 100644
--- a/node_modules/ace/lib/ace/edit_session.js
+++ b/node_modules/ace/lib/ace/edit_session.js
@@ -1158,7 +1158,7 @@ EditSession.$uid = 0;
                 this.addFolds(delta.folds);
             }
         }
-        if (!dontSelect) {
+        if (!dontSelect && this.$undoSelect) {
             // console.log(deltas.selectionBefore + "uuu")
             if (deltas.selectionBefore)
                 this.selection.fromJSON(deltas.selectionBefore);
@@ -1187,7 +1187,7 @@ EditSession.$uid = 0;
             }
         }
 
-        if (!dontSelect) {
+        if (!dontSelect && this.$undoSelect) {
             if (deltas.selectionAfter)
                 this.selection.fromJSON(deltas.selectionAfter);
             else
diff --git a/node_modules/ace/lib/ace/layer/font_metrics.js b/node_modules/ace/lib/ace/layer/font_metrics.js
index 7fea61e4..3959cb29 100644
--- a/node_modules/ace/lib/ace/layer/font_metrics.js
+++ b/node_modules/ace/lib/ace/layer/font_metrics.js
@@ -172,7 +172,7 @@ var FontMetrics = exports.FontMetrics = function(parentEl, interval) {
     this.getCharacterWidth = function(ch) {
         var w = this.charSizes[ch];
         if (w === undefined) {
-            this.charSizes[ch] = this.$measureCharWidth(ch) / this.$characterSize.width;
+            w = this.charSizes[ch] = this.$measureCharWidth(ch) / this.$characterSize.width;
         }
         return w;
     };
diff --git a/node_modules/ace/lib/ace/placeholder.js b/node_modules/ace/lib/ace/placeholder.js
index 0e299594..c4c88b11 100644
--- a/node_modules/ace/lib/ace/placeholder.js
+++ b/node_modules/ace/lib/ace/placeholder.js
@@ -70,7 +70,7 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
     this.$pos = pos;
     // Used for reset
     var undoStack = session.getUndoManager().$undoStack || session.getUndoManager().$undostack || {length: -1};
-    this.$undoStackDepth =  undoStack.length;
+    this.$undoStackDepth = undoStack.length;
     this.setup();
 
     session.selection.on("changeCursor", this.$onCursorChange);
@@ -90,21 +90,21 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
         var _self = this;
         var doc = this.doc;
         var session = this.session;
-        var pos = this.$pos;
         
         this.selectionBefore = session.selection.toJSON();
         if (session.selection.inMultiSelectMode)
             session.selection.toSingleRange();
 
-        this.pos = doc.createAnchor(pos.row, pos.column);
-        this.markerId = session.addMarker(new Range(pos.row, pos.column, pos.row, pos.column + this.length), this.mainClass, null, false);
-        this.pos.on("change", function(event) {
-            session.removeMarker(_self.markerId);
-            _self.markerId = session.addMarker(new Range(event.value.row, event.value.column, event.value.row, event.value.column+_self.length), _self.mainClass, null, false);
-        });
+        this.pos = doc.createAnchor(this.$pos.row, this.$pos.column);
+        var pos = this.pos;
+        pos.$insertRight = true;
+        pos.detach();
+        pos.markerId = session.addMarker(new Range(pos.row, pos.column, pos.row, pos.column + this.length), this.mainClass, null, false);
         this.others = [];
         this.$others.forEach(function(other) {
             var anchor = doc.createAnchor(other.row, other.column);
+            anchor.$insertRight = true;
+            anchor.detach();
             _self.others.push(anchor);
         });
         session.setUndoSelect(false);
@@ -117,16 +117,12 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
      *
      **/
     this.showOtherMarkers = function() {
-        if(this.othersActive) return;
+        if (this.othersActive) return;
         var session = this.session;
         var _self = this;
         this.othersActive = true;
         this.others.forEach(function(anchor) {
             anchor.markerId = session.addMarker(new Range(anchor.row, anchor.column, anchor.row, anchor.column+_self.length), _self.othersClass, null, false);
-            anchor.on("change", function(event) {
-                session.removeMarker(anchor.markerId);
-                anchor.markerId = session.addMarker(new Range(event.value.row, event.value.column, event.value.row, event.value.column+_self.length), _self.othersClass, null, false);
-            });
         });
     };
     
@@ -137,7 +133,7 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
      *
      **/
     this.hideOtherMarkers = function() {
-        if(!this.othersActive) return;
+        if (!this.othersActive) return;
         this.othersActive = false;
         for (var i = 0; i < this.others.length; i++) {
             this.session.removeMarker(this.others[i].markerId);
@@ -151,64 +147,61 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
      *
      **/
     this.onUpdate = function(delta) {
+        if (this.$updating)
+            return this.updateAnchors(delta);
+            
         var range = delta;
-        if(range.start.row !== range.end.row) return;
-        if(range.start.row !== this.pos.row) return;
-        if (this.$updating) return;
+        if (range.start.row !== range.end.row) return;
+        if (range.start.row !== this.pos.row) return;
         this.$updating = true;
         var lengthDiff = delta.action === "insert" ? range.end.column - range.start.column : range.start.column - range.end.column;
+        var inMainRange = range.start.column >= this.pos.column && range.start.column <= this.pos.column + this.length + 1;
+        var distanceFromStart = range.start.column - this.pos.column;
         
-        if(range.start.column >= this.pos.column && range.start.column <= this.pos.column + this.length + 1) {
-            var distanceFromStart = range.start.column - this.pos.column;
+        this.updateAnchors(delta);
+        
+        if (inMainRange)
             this.length += lengthDiff;
-            if(!this.session.$fromUndo) {
-                if(delta.action === 'insert') {
-                    for (var i = this.others.length - 1; i >= 0; i--) {
-                        var otherPos = this.others[i];
-                        var newPos = {row: otherPos.row, column: otherPos.column + distanceFromStart};
-                        if(otherPos.row === range.start.row && range.start.column < otherPos.column)
-                            newPos.column += lengthDiff;
-                        this.doc.insertMergedLines(newPos, delta.lines);
-                    }
-                } else if(delta.action === 'remove') {
-                    for (var i = this.others.length - 1; i >= 0; i--) {
-                        var otherPos = this.others[i];
-                        var newPos = {row: otherPos.row, column: otherPos.column + distanceFromStart};
-                        if(otherPos.row === range.start.row && range.start.column < otherPos.column)
-                            newPos.column += lengthDiff;
-                        this.doc.remove(new Range(newPos.row, newPos.column, newPos.row, newPos.column - lengthDiff));
-                    }
+
+        if (inMainRange && !this.session.$fromUndo) {
+            if (delta.action === 'insert') {
+                for (var i = this.others.length - 1; i >= 0; i--) {
+                    var otherPos = this.others[i];
+                    var newPos = {row: otherPos.row, column: otherPos.column + distanceFromStart};
+                    this.doc.insertMergedLines(newPos, delta.lines);
                 }
-                // Special case: insert in beginning
-                if(range.start.column === this.pos.column && delta.action === 'insert') {
-                    setTimeout(function() {
-                        this.pos.setPosition(this.pos.row, this.pos.column - lengthDiff);
-                        for (var i = 0; i < this.others.length; i++) {
-                            var other = this.others[i];
-                            var newPos = {row: other.row, column: other.column - lengthDiff};
-                            if(other.row === range.start.row && range.start.column < other.column)
-                                newPos.column += lengthDiff;
-                            other.setPosition(newPos.row, newPos.column);
-                        }
-                    }.bind(this), 0);
+            } else if (delta.action === 'remove') {
+                for (var i = this.others.length - 1; i >= 0; i--) {
+                    var otherPos = this.others[i];
+                    var newPos = {row: otherPos.row, column: otherPos.column + distanceFromStart};
+                    this.doc.remove(new Range(newPos.row, newPos.column, newPos.row, newPos.column - lengthDiff));
                 }
-                else if(range.start.column === this.pos.column && delta.action === 'remove') {
-                    setTimeout(function() {
-                        for (var i = 0; i < this.others.length; i++) {
-                            var other = this.others[i];
-                            if(other.row === range.start.row && range.start.column < other.column) {
-                                other.setPosition(other.row, other.column - lengthDiff);
-                            }
-                        }
-                    }.bind(this), 0);
-                }
-            }
-            this.pos._emit("change", {value: this.pos});
-            for (var i = 0; i < this.others.length; i++) {
-                this.others[i]._emit("change", {value: this.others[i]});
             }
         }
+        
         this.$updating = false;
+        this.updateMarkers();
+    };
+    
+    this.updateAnchors = function(delta) {
+        this.pos.onChange(delta);
+        for (var i = this.others.length; i--;)
+            this.others[i].onChange(delta);
+        this.updateMarkers();
+    };
+    
+    this.updateMarkers = function() {
+        if (this.$updating)
+            return;
+        var _self = this;
+        var session = this.session;
+        var updateMarker = function(pos, className) {
+            session.removeMarker(pos.markerId);
+            pos.markerId = session.addMarker(new Range(pos.row, pos.column, pos.row, pos.column+_self.length), className, null, false);
+        };
+        updateMarker(this.pos, this.mainClass);
+        for (var i = this.others.length; i--;)
+            updateMarker(this.others[i], this.othersClass);
     };
     
     /**
@@ -237,14 +230,10 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
      *
      **/    
     this.detach = function() {
-        this.session.removeMarker(this.markerId);
+        this.session.removeMarker(this.pos && this.pos.markerId);
         this.hideOtherMarkers();
         this.doc.removeEventListener("change", this.$onUpdate);
         this.session.selection.removeEventListener("changeCursor", this.$onCursorChange);
-        this.pos.detach();
-        for (var i = 0; i < this.others.length; i++) {
-            this.others[i].detach();
-        }
         this.session.setUndoSelect(true);
         this.session = null;
     };
@@ -256,8 +245,8 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
      *
      **/
     this.cancel = function() {
-        if(this.$undoStackDepth === -1)
-            throw Error("Canceling placeholders only supported with undo manager attached to session.");
+        if (this.$undoStackDepth === -1)
+            return;
         var undoManager = this.session.getUndoManager();
         var undosRequired = (undoManager.$undoStack || undoManager.$undostack).length - this.$undoStackDepth;
         for (var i = 0; i < undosRequired; i++) {
diff --git a/package.json b/package.json
index a12f2ace..ffece52c 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
         "c9"
     ],
     "c9plugins": {
-        "c9.ide.language": "#a6ffafabce",
+        "c9.ide.language": "#58aa87f576",
         "c9.ide.language.css": "#a649f2a710",
         "c9.ide.language.generic": "#77d43cfaf0",
         "c9.ide.language.html": "#0f4078c187",
@@ -106,7 +106,7 @@
         "c9.ide.run.build": "#0598fff697",
         "c9.ide.run.debug.xdebug": "#61dcbd0180",
         "c9.ide.save": "#4a4a60a004",
-        "c9.ide.scm": "#7b0c0714b4",
+        "c9.ide.scm": "#f0365ca725",
         "c9.ide.terminal.monitor": "#b76f1c9f24",
         "c9.ide.test": "#ebc037901c",
         "c9.ide.test.mocha": "#586fb0cdc2",
diff --git a/plugins/c9.ide.tree/style.css b/plugins/c9.ide.tree/style.css
index 7137f666..7d23332f 100644
--- a/plugins/c9.ide.tree/style.css
+++ b/plugins/c9.ide.tree/style.css
@@ -20,7 +20,7 @@
     color : @selected-color;
 }
 
-.filetree .tree-row.projectRoot, .filetree .tree-row:first-child {
+.filetree .tree-row.projectRoot:first-child {
     margin-right: @tree-first-row-margin-right;
 }
 
diff --git a/plugins/c9.ide.tree/tree.js b/plugins/c9.ide.tree/tree.js
index 788068a8..477b0540 100644
--- a/plugins/c9.ide.tree/tree.js
+++ b/plugins/c9.ide.tree/tree.js
@@ -277,6 +277,7 @@ define(function(require, exports, module) {
             btnTreeSettings.setAttribute("submenu", mnuFilesSettings);
             tree.renderer.on("scrollbarVisibilityChanged", updateScrollBarSize);
             tree.renderer.on("resize", updateScrollBarSize);
+            tree.renderer.scrollBarV.$minWidth = 10;
             function updateScrollBarSize() {
                 var scrollBarV = tree.renderer.scrollBarV;
                 var w = scrollBarV.isVisible ? scrollBarV.getWidth() : 0;