Revit Tooltip freezing screen

Question
Why do tooltips freeze on screen when using a projector?

Answer
Running Revit on a second monitor or projector can cause this problem. See Autodesk Revit Products troubleshooting page.

http://knowledge.autodesk.com/support/revit-products/troubleshooting/caas/sfdcarticles/sfdcarticles/Revit-Tooltip-freezing-screen.html