I have a toolbar and explorer bar on my form.when ever i drag and drop the group box (explorer bar) at the toolbar the below exception is occurred. This is the stack trace of my exception. "at Infragistics.Win.UltraWinExplorerBar.UltraExplorerBar.ItemFromPoint(Point point) at Infragistics.Win.UltraWinExplorerBar.UltraExplorerBar.Infragistics.Win.UltraWinExplorerBar.IItemContainer.ItemFromPoint(Point point) at Infragistics.Win.UltraWinExplorerBar.UltraExplorerBar.Infragistics.Win.ISelectionManager.OnMouseUp(MouseMessageInfo& msginfo) at Infragistics.Win.SelectionStrategySingle.OnMouseMessage(ISelectableItem item, MouseMessageInfo& msginfo) at Infragistics.Win.ControlUIElementBase.ProcessMouseUpHelper(Object sender, MouseEventArgs e) at Infragistics.Win.ControlUIElementBase.ProcessMouseUp(Object sender, MouseEventArgs e) at Infragistics.Win.Utilities.ProcessEvent(Control control, ProcessEvent eventToProcess, EventArgs e) at Infragistics.Win.UltraControlBase.OnMouseUp(MouseEventArgs e) at Infragistics.Win.UltraWinExplorerBar.UltraExplorerBar.OnMouseUp(MouseEventArgs e) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run() at Coronado.Framework.PFM.Program.Main() in F:\SVN\UI\desktop\Framework\PFM\Program.cs:line 84 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[ args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[ args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()" Could any one tell me how to avoid this exception. Best Regards, nouman shehzad