Ok...I'm not sure if this is the solution but documenting what I did to get it to work.
1) shut down thingworx studio
2) Clear chrome history and close Chrome
3) rename user data folder "C:\Users\xxx\AppData\Local\Google\Chrome\User Data" to User Data Old
4) shut down and restart computer
5) launch thingworx studio and go to project - still had gray screen.
6) shut down thingworx and clear chrome history(cache) again.
7) close Chrome and delete newly created user data folder for google chrome.
8) rename User Data Old back to User Data.
9) Shut down computer and restart everything.
I have a feeling there is a reset of something in that process that is getting my graphics back...will retest if it occurs again.
It's also worth noting that I had gray screen for the 3 days prior to the release of Studio version 1.9. It worked for a day after upgrading to 1.9 then the next launch it went gray...then did steps above to get it back.