XmUpdateDisplay - A function that processes all pending exposure events immediately
XmUpdateDisplay provides the application with a mechanism for forcing all pending exposure events to be removed from the input queue and processed immediately. When a user selects a button within a MenuPane, the MenuPanes are unposted and then any activation callbacks registered by the application are invoked. If one of the callbacks performs a time-consuming action, the portion of the application window that was covered by the MenuPanes will not have been redrawn; normal exposure processing does not occur until all of the callbacks have been invoked. If the application writer suspects that a callback will take a long time, then the callback may choose to invoke XmUpdateDisplay before starting its time-consuming operation. This function is also useful any time a transient window, such as a dialog box, is unposted; callbacks are invoked before normal exposure processing can occur. Specifies any widget or gadget.