Darwin, unless you are really flying through your RTS, I don't think that you're quite up to the stage where you need to draw the selection circles around units.
What I did for my RTS was;
Function _mouse_selection()
po = Pick Object(mx,my,1,100)
`basically, po = the object just selected.
If po <> 0
units(po).selected = 1 : Color Object po,RGB(0,100,0)
Else
For x = 1 To unitlimit
If units(x).selected = 1 Then units(x).selected = 0 : Color Object x,RGB(255,255,255)
Next x
EndIf
EndFunction
You can see I am using Types, and the selected flag is set to one when it is selected, and at the same time, I colour the object green.
Then, when the selected flag goe's back to 0, i colour the object white again.
This just a temporary thing, untill I get the engine sorted out, and up to the stage where I can add eye candy.
Hope I Helped...
Team EOD :: Programmer/Logical Engineer/All-Round Nice Guy