XPLMMouseStatus

When the mouse is clicked, your mouse click routine is called repeatedly. It is first called with the mouse down message. It is then called zero or more times with the mouse-drag message, and finally it is called once with the mouse up message. All of these messages will be directed to the same window; you are guaranteed to not receive a drag or mouse-up event without first receiving the corresponding mouse-down.

NameValueDescription
xplm_MouseDown"1"
xplm_MouseDrag"2"
xplm_MouseUp"3"