Crash when accessing window of protected process

[mastersign]

If the window enumeration encounters a window of a process, running with elevated rights, the application crashes with the following exception:

System.ComponentModel.Win32Exception (0x80004005): Access is denied
   at System.Diagnostics.ProcessManager.OpenProcess(Int32 processId, Int32 access, Boolean throwIfExited)
   at System.Diagnostics.NtProcessManager.GetModuleInfos(Int32 processId, Boolean firstModuleOnly)
   at System.Diagnostics.NtProcessManager.GetFirstModuleInfo(Int32 processId)
   at System.Diagnostics.Process.get_MainModule()
   at Mastersign.WinMan.WindowPattern.FromWindow(WindowWrapper w)
   at Mastersign.WinMan.Gui.MainForm.NewWindowPatternHandler(Object sender, EventArgs e)
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)