Ensure the graphics card driver is upto date. You can also then try with the following setting
1. Navigate to Java Control Panel> Java> Java Runtime Environment > User
2. Add line to Runtime Parameter field:
-Dsun.java2d.d3d=false -Dsun.java2d.noddraw=true
3. Restart Workflow Administrator
4. Also clear the Java cache.
Hope that helps.
regards
~Syed