Turn off click boxes highlight when Tab is pressed

I'm having issues with the behavior of click boxes in a system simulation.

To overcome an issue with a Tab+Return sequence restarting the module, I published with  'restrict keyboard tabbing to slide items' checked. This fixed the restart issue, but then allowed a user to tab through all objects on a screen (with a visible yellow border highlight on the object).  

I next published with 'accessibility' unchecked. This prevents the (visible) tabbing through all screen objects, but now the click box gets the yellow border highlight when Tab is pressed. 

How do I totally eliminate these yellow border highlights? I didn't see anything in the forum, and can't seem to find a setting for this.

Thanks