Please describe the problem:
When executing a script-fu script in either GIMP 2.3.11 or 2.3.12 on Windows, e.g. blur non-edges script, if I select another GIMP window to bring focus to it, the script stops executing and the whole app freezes unless the script-fu process (which doesn't seem to use utilise the CPU) is killed. Happens with any script I try.
If there is an operation carried out by the script before this event occurs, the undo function doesn't seem to be able to go back (and the image is marked as a changed one in the window title bar).

Steps to reproduce:
1. Load an image in the GIMP.
2. Right click the image, go to the script-fu menu, pick any script-fu script.
3. Let it run but before it finishes executing, select another GIMP window (outside the script window) using the left mouse button (if it's the button assigned to using the currently selected tool).


Actual results:
The whole program stops responding, the script won't finish, even if its execution would take about 5-10 seconds otherwise.

Expected results:
I presume one should be able to get back to the script window (if it's still running) without freezing the script-fu execution (and GIMP).

Does this happen every time?
Yes.

Other information: