I recently tried something similar to this to hold down the [Alt] key while clicking on a save button, which in the application in question forces certain additional options to be saved. This method was not working for me until I added "Sleep(100)" after the Mouseclick function (actually, I was using a ControlClick, but it's the same idea).
After I figured this out, I realized this was necessary to ensure that the [Alt] key stayed down long enough after the click for the program I was controlling to register it. I thought I might save someone else some time by pointing this out.
