linking GUI

I usually say, at the beginning of every loop:

MouseClick = MouseHit(1)
MouseUp = (MouseDn=1) And (MouseDown(1)=0)
MouseDn = MouseDown(1)
MXspd = MouseXSpeed()
MYspd = MouseYSpeed()
MZspd = MouseZSpeed()

That usually takes care of everything. It would of course need to be modified if you want to take into account right-clicks. (MouseHit(2))