Lock editing of scene when file dialog is open

On Linux many many users use focus follows mouse. And love it.

But this causes a problem when the mouse slips off of the file dialog when editing a file name.

On more than one occasion I have opened a file -> save as dialog box and am trying to edit the name of the file that is pre-populated. But my mouse will slip off of the dialog and onto the 3D view panel. Then when I hit any key (like delete, or shift-D to type a capital D in my file name, or x to type an 'x", or... you get the idea) these keys are interpreted as commands in the 3D view. If I am lucky, I catch the issue where my scene has suddenly been altered when all I am trying to do is type a file name. Then I have to cancel and go to my undo history and try to figure out what was a legitimate command issued when I was working vs. an accidental command because my file name was instead interpreted as a series of editing operations.

If I am unlucky (and I am often unlucky) I won't notice that I made a bunch of subtle, unwanted changes to my scene right before I saved. And then I might not even notice till the next time I opened up my project and nothing is the way it is supposed to be but I can't remember what I might have done to break things.

This is fairly serious.

Ideally when a file dialog is open, we should not be able to edit the scene underneath. It should be a blocking dialog.