RobotStudio event

Problems with screen update using RS 5.15 under Win7

When I use Robotstudio 5.15 on my Win7 Laptop I have the problem that the screen does not update. Example: I change Rapidcode but can not seen what I type. Only when changing Window size or minimize and reopen, Changes are displayed. Same happens when opening/closing the task-tree.
Same RS release on my Desktop PC (Win7) runs fine.
Any suggestions how to solve this?
I already checked for latest Graphicdriver.

Best regards.