It's not so much a time out issue as a design one.
When the dialog pops up it will not close.
I have tried clicking X, ESC clicking on the background, nothing. The dialog stays up preventing the save.
There's nothing to be done other than F5, which loses any unsaved work. Surely if an editor is active the user should not be locked out of it!?
As I said, it's crazy.
The Joomla editor (JCE pro in our case) doesn't behave like that and stays alive so long as editing work is going on.