AC 11 has no problems for me on Leopard.
AC 10 - which was not developed for Leopard - has a minor glitch that I just noticed yesterday with a client/friend. If your plan window is on your primary monitor, the print dialog shows up properly. If the plan window has been dragged to a secondary monitor, none of the checkboxes or preview appear in the print dialog when it is showing the ArchiCAD panel.
Karl
