Hi Pedro DaSilva,
I have exactly same version on my Laptop and it works fine.
Did the upgrade happened successfully. Are there any errors in the logs?
Try restarting the Application and browser to see if it helps. You may also want to restart the system too.
If it still persist; take a backup of Projects at <User_Home>\Documents\ThingWorxStudio\Projects and try reinstalling the Application.
For testing only; I would suggest you check on other browsers too.