Survex 1.2.8: Aven can't get out of full screen mode

[Rowena Larkins]

I installed survex 1.2.8 on my Windows 7 professional I7 desktop at the end of October last year.
It seemed to be working fine.
I selected the menu option in Aven to view the legs in full screen mode and now I cannot get Aven to return to windowed mode and work properly.
In full screen mode there is no menu, however I am able to use keyboard shortcuts to move my rendering.
Also no other windows can be brought to the front. All I can do with my pc is move a survey 3d file in aven.

When I press the F11 key, Aven returns to a window, however there is no menu bar, and the window does not respond to any events. The only way to close the window is to use the task manager.
When in windowed mode there are no survey legs showing, only a black screen. 

I have shutdown the machine several times and Aven still starts in full screen mode.

In the short term I have reverted to Survex 1.2.7 which is behaving itself.

Can you assist me in understanding why aven 1.2.8 only starts now in full screen mode; is there a config file somewhere I can modify so it starts in windowed mode?

Thanks,

Rowena