gimp move by holding space bar does not terminate

[Gordon Fitch]

package: gimp 2.8.14

release: Ubuntu 14.04.3 LTS

circumstance: Running gimp in full screen mode, moving image around by depressing space bar and using mouse. Cursor changes to fist. Note that image was larger by a good bit than window / view of image.

expected behavior: On releasing space bar, cursor should resume previous mode and moving mouse should not move image.

observed behavior: On releasing space bar, gimp remains in same state (moving image). Moving the cursor outside the window does not release the move either. Clicking mouse (either side) has no effect in window or out. Nor does ESC, space, break, or any other keyboard action. In full screen mode, it is necessary to reboot or restart the desktop to get out of the situation.

[Gordon Fitch (gcf)]

I should add that the problem is intermittent -- not seen often.

[Gordon Fitch (gcf)]

Same version, same problem, not running fullscreen mode. Cannot escape hangup because the mouse and graphics tablet inputs continue to be captured (I assume). When I signed on from another computer via ssh and killed the Gimp process, everything else appeared to resume running normally.