I may just be missing a simple call; but how do I find out if the shift, ctrl, and or alt keys are pressed when the mouse is clicked? For example, I may want to click on several objects on the screen, if the shift key is down I want to add the clicked object to the selection, but if not, I want to replace the selection with the newly clicked item. I've got everything I need to do this, but I don't know how to find out if the shift key is down when the click happens (without resorting to win32 api calls).