A Message sent when the user presses the mouse button. If there was a message handler by the same name in the message path, then it would be executed.
Parameter "mouseButtonNumber" is the number of the mouse button pressed - 1 is the mouse button on Mac OS systems and the left button on Windows and Unix systems, 2 is the middle button on Unix systems & 3 is the right button on Windows and Unix systems and Control-click on Mac OS systems.
Use the mouseDown message handler to perform an action when the user presses the mouse button, before the mouse button is released.
If the Browse tool is being used, and you click an unlocked field with mouse button 1 or 2, no mouseDown message is sent. If you click with button 3, the mouseDown message is sent even though the field is not locked.
on mouseDown theButton -- show popup menu on Control/Right-click if theButton is 3 then popup button "Configure" else pass mouseDown end mouseDown