This is most likely a Flash-related issue. There are a few ways to solve this:
- Reset UI by going to Settings at the top right corner.
- If this problem still exists, then update to current Flash version and check that your machine is meeting minimum system tech requirements. A good site to check if your computer meets our minimum requirements is www.supportdetails.com.
- Finally, if you are still experiencing this issue, reset the Flash cache by right-clicking on an image and hit Global Settings. Select Delete All.
More about Flash and UI:
GLOBALedit Minimum Requirements / Tech Specs