i think a scenario this feature would useful is the following:
Assuming we have an open dialog contain user profile info.
1) user wants to change name
2) user edits name and presses save button
3) a "please wait...." message appears
4) "saved successfully" message appears
5) then user closes dialog
For step 3 & 4, we don't want to the user to be able to click on any buttons or change any inputs
-Harrison