Args
ARG(1) indicates whether the CTRL and/or SHIFT keys are being held down, and/or whether the middle/left/right buttons are held down. You can use BIT's TEST operation to ascertain which as so:
IF BIT(ARG(1), 0) THEN SAY "left button pressed" IF BIT(ARG(1), 1) THEN SAY "right button pressed" IF BIT(ARG(1), 4) THEN SAY "Middle button held down" IF BIT(ARG(1), 2) THEN SAY "SHIFT key pressed" IF BIT(ARG(1), 3) THEN SAY "CTRL key pressed"ARG(2) is the X position where the mouse pointer is currently located (referenced from the upper left corner of the window's inner area), and ARG(3) is the Y position.
Notes
This event happens only DBLCLKS option when calling GuiWindowDefaults. The event happens whenever the user presses, releases, and again presses the middle mouse button within the system's double-click time limit. Double-clicking the mouse mouse button actually generates four events: MBUTTONDOWN, MBUTTONUP, MBUTTONDBLCLK, and MBUTTONUP again.
If the mouse is captured by some window, then the event happens only with the window capturing the mouse.
See also MBUTTONDOWN.