use the stick method first pioneered by lucid in a thread about a 2d katamari damacy clone
in the following cap you can see it in action, it's not nearly as confusing as it sounds or looks
you don't need as many events as I have there, so try to figure out what they're each doing
I only put so many so you can see that it works in all situations
drag and drop the green or blue boxes
and hold the right mouse button to stop the green one from rotating, and rotate the blue one
in your actual cap, you'll obviously make the line sprite invisible
http://files.getdropbox.com/u/1013446/anglethingy.cap
(saved in 99.3)
you make a sprite of horizontal line with the hotspot at the very left, and an imagepoint at the very right
then when it's time to stick an object B to object A
you set the line position to Object A position
set line width to distance(objecta.x,objecta.y,objectb.x,objectb.y)
and set angle of the line sprite to angle(objecta.x,objecta.y,objectb.x,objectb.y)
and set a private variable ORIGLINEANG to linesprite.angle-objecta.angle
and set a private variable ORIGANGB to objectb.angle
then you 'Always' set line sprite position to object a position, and 'always' set object b position to line position at imagepoint 1
always set line angle to objecta.angle+ORIGLINEANG
and 'always' set angle of objectb to objecta.angle+ORIGANGB