Possible Bug 3.7 - System hanging and non responsive

I was just updating an image used in a layer trait. Now the whole Vassal module has entered a ‘hang mode’. Cannot do anything with it. Module is not using any CPU time, except for the very occasional 1 to 2%. The error log last entry relates to the ‘refresh counters’ I had run some time before.

Used task manager to close it down. Reloaded and there were no problems with updating the image.