I have been using MWG 7.x and web reporter since before they were released. I have never seen screen layout problems like you show, either on my own systems or on the thousands of WebEx's with customers either directly in the GUI or through an RDP session.
However, 99% of the time, we all use windows. On the RARE occasion is use a Mac or a customer uses a Mac, I have not seen those symptoms either.
My guess is it has something to do with the RDP from OSX. Have you tried any alternate RDP clients?
Also, if you have the opportunity, load up 7.6.x onto a test VM guest and try the native java web start app. I wonder if it will behave the same.
I think I finally fixed it. I was unable to replicate in Win10 on a different box. I think somehow the Mac RDP client got into a custom resolution mode for full screen rather than full screen os x native.
Thanks all for hte input.