gEDA-user: PCB and stroke

[Xtian Xultz <xultz@ig.com.br>]

I was taking a look at the configure options of the newest tarball
of Pcb.
I see there is a option called --without-libstroke.
A few days ago I had a little problem using Pcb compiled with strokes,
in a machine with a mouse with scroll button (it was a Microsoft 
Intellimouse with Scroll, with the middle button below the scroll
wheel). With libstroke enabled, when I press the middle button and
drag to create a selection box, it dont make it, but when I drag 
diagonnaly it makes a zoom! I could not select objects, and so on.
Then, I compile with the option --without-libstroke and the middle
button worked fine, as expected.

Today, I compiled the tarball in my machine with stroke enabled. I
have a very simple serial mouse with three buttons, and the middle
button worked as expected, without any reference to strokes...
My question is, how and what the strokes do in PCB? Is like the strokes
support in gEDA?