diff --git a/samples/SdaUser/SdaAddIns/SdaBase.addin b/samples/SdaUser/SdaAddIns/SdaBase.addin
index 66291b2c40..daf35919d8 100644
--- a/samples/SdaUser/SdaAddIns/SdaBase.addin
+++ b/samples/SdaUser/SdaAddIns/SdaBase.addin
@@ -14,12 +14,12 @@
 		<Import assembly=":ICSharpCode.SharpDevelop">
 			<!-- SharpDevelop defines more conditions and doozers, we just -->
 			<!-- import those we need here. -->
-			<ConditionEvaluator name="WindowActive" class="ICSharpCode.Core.WindowActiveConditionEvaluator"/>
-			<ConditionEvaluator name="ActiveWindowState" class="ICSharpCode.Core.ActiveWindowStateConditionEvaluator"/>
-			<ConditionEvaluator name="OpenWindowState" class="ICSharpCode.Core.OpenWindowStateConditionEvaluator"/>
+			<ConditionEvaluator name="WindowActive" class="ICSharpCode.SharpDevelop.WindowActiveConditionEvaluator"/>
+			<ConditionEvaluator name="ActiveWindowState" class="ICSharpCode.SharpDevelop.ActiveWindowStateConditionEvaluator"/>
+			<ConditionEvaluator name="OpenWindowState" class="ICSharpCode.SharpDevelop.OpenWindowStateConditionEvaluator"/>
 			
-			<Doozer name="DialogPanel" class="ICSharpCode.Core.DialogPanelDoozer"/>
-			<Doozer name="DisplayBinding" class="ICSharpCode.Core.DisplayBindingDoozer"/>
+			<Doozer name="DialogPanel" class="ICSharpCode.SharpDevelop.DialogPanelDoozer"/>
+			<Doozer name="DisplayBinding" class="ICSharpCode.SharpDevelop.DisplayBindingDoozer"/>
 		</Import>
 	</Runtime>
 	
diff --git a/src/Main/Base/Project/Src/Gui/Components/ExtTreeView/ExtTreeView.cs b/src/Main/Base/Project/Src/Gui/Components/ExtTreeView/ExtTreeView.cs
index 5dbf356462..3dad04c927 100644
--- a/src/Main/Base/Project/Src/Gui/Components/ExtTreeView/ExtTreeView.cs
+++ b/src/Main/Base/Project/Src/Gui/Components/ExtTreeView/ExtTreeView.cs
@@ -374,14 +374,7 @@ namespace ICSharpCode.SharpDevelop.Gui
 			ExtTreeNode node             = GetNodeAt(clientcoordinate) as ExtTreeNode;
 			
 			if (node != null) {
-				DragDropEffects effect = DragDropEffects.None;
-				
-				if ((e.KeyState & 8) > 0) { // CTRL key pressed.
-					effect = DragDropEffects.Copy;
-				} else {
-					effect = DragDropEffects.Move;
-				}
-				e.Effect = node.GetDragDropEffect(e.Data, effect);
+				HandleDragOver(e, node);
 				
 				if (e.Effect != DragDropEffects.None) {
 					SelectedNode = node;
@@ -389,6 +382,18 @@ namespace ICSharpCode.SharpDevelop.Gui
 			}
 		}
 		
+		void HandleDragOver(DragEventArgs e, ExtTreeNode node)
+		{
+			DragDropEffects effect = DragDropEffects.None;
+			
+			if ((e.KeyState & 8) > 0) { // CTRL key pressed.
+				effect = DragDropEffects.Copy;
+			} else {
+				effect = DragDropEffects.Move;
+			}
+			e.Effect = node.GetDragDropEffect(e.Data, effect);
+		}
+		
 		protected override void OnDragDrop(DragEventArgs e)
 		{
 			base.OnDragDrop(e);
@@ -396,8 +401,15 @@ namespace ICSharpCode.SharpDevelop.Gui
 			ExtTreeNode node             = GetNodeAt(clientcoordinate) as ExtTreeNode;
 			
 			if (node != null) {
-				node.DoDragDrop(e.Data, e.Effect);
-				SortParentNodes(node);
+				// when dragging very fast from one node to another, it's possible that
+				// OnDragDrop raises without OnDragOver for the node.
+				// So we have to call HandleDragOver to ensure that we don't call DoDragDrop for
+				// invalid operations.
+				HandleDragOver(e, node);
+				if (e.Effect != DragDropEffects.None) {
+					node.DoDragDrop(e.Data, e.Effect);
+					SortParentNodes(node);
+				}
 			}
 		}
 		
diff --git a/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/ProjectBrowserPanel.cs b/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/ProjectBrowserPanel.cs
index 4365e38f9a..3060087094 100644
--- a/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/ProjectBrowserPanel.cs
+++ b/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/ProjectBrowserPanel.cs
@@ -45,14 +45,16 @@ namespace ICSharpCode.SharpDevelop.Project
 			projectBrowserControl.Dock = DockStyle.Fill;
 			Controls.Add(projectBrowserControl);
 			
-			toolStrip = ToolbarService.CreateToolStrip(this, "/SharpDevelop/Pads/ProjectBrowser/ToolBar/Standard");
-			toolStrip.ShowItemToolTips  = true;
-			toolStrip.Dock = DockStyle.Top;
-			toolStrip.GripStyle = System.Windows.Forms.ToolStripGripStyle.Hidden;
-			toolStrip.Stretch   = true;
-			standardItems = new ToolStripItem[toolStrip.Items.Count];
-			toolStrip.Items.CopyTo(standardItems, 0);
-			Controls.Add(toolStrip);
+			if (AddInTree.ExistsTreeNode("/SharpDevelop/Pads/ProjectBrowser/ToolBar/Standard")) {
+				toolStrip = ToolbarService.CreateToolStrip(this, "/SharpDevelop/Pads/ProjectBrowser/ToolBar/Standard");
+				toolStrip.ShowItemToolTips  = true;
+				toolStrip.Dock = DockStyle.Top;
+				toolStrip.GripStyle = System.Windows.Forms.ToolStripGripStyle.Hidden;
+				toolStrip.Stretch   = true;
+				standardItems = new ToolStripItem[toolStrip.Items.Count];
+				toolStrip.Items.CopyTo(standardItems, 0);
+				Controls.Add(toolStrip);
+			}
 			projectBrowserControl.TreeView.BeforeSelect += TreeViewBeforeSelect;
 		}
 		
@@ -63,6 +65,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		void UpdateToolStrip(AbstractProjectBrowserTreeNode node)
 		{
+			if (toolStrip == null) return;
 			toolStrip.Items.Clear();
 			toolStrip.Items.AddRange(standardItems);
 			ToolbarService.UpdateToolbar(toolStrip);