Difficulty Unselecting Layers (beta only)

Before I reset 24.7 beta Preferences _again_ I'll run it by the forum.  

I have a document with eight layers.  We can usually unselect all layers by clicking on the empty space below the layers, but this is no longer working.  The active layer remains selected.  In fact AFAICT it is impossible to unselect all layers. 

I have tried restarting 24.7, and creating a new document without change.

I switched to the full release version that works as usual.

My workaround so far is to select the backround layer.

It's possible my beta installation has been doing this all along, but its pretty annoying so I am thinking probably not.  If someone wouldn't mind testing this and letting me know, so I can reset Preference AGAIN Grrrr... if it's going to fix this.

Thank you