#2648 tk_messageBox unresponsive on global grab

[Harald Oehlmann]

A message box is inresponsive, if there is a global grab on another widget.

Example:
pack [button .b -text t -command "tk_messageBox"]
focus .b
raise .
grab -global .b

This might be seen as feature, but it might be helpful, to replace the grab of message box by the existing grab, and restore it afterwards.

On Windows XP, tk 8.5.7