[Xastir] Configuration of operation not clear

[Rice, MA Mark @ IS]

I made my 1st APRS transmission with an ancient HK232 last night.  It
seemed to work!

But I'm confused about a menu item that sets up some operational aspect
of Xastir. There's setup window for what appeared to be timing of
messages or beacons... I'm guessing.  There was no text in the setup
window... just sliders.  (My apologies.. I'm not close to the Linux
machine right now and I don't recall what menu item brings this up).  

There wasn't anything printed next the individual "sliders" in the
window... just a set of sliders that you could position with the mouse.
I wasn't sure what those affected... so I left them at default.

Can someone point out what those sliders are for, or direct me to an
online page that discusses it?  I tried looking through the
documentation, but couldn't seem to find anything.   I'm presuming that
my Linux (Fedora Core 5) has something missing, otherwise I'd see text
in that window.

Thanks so much,

- Mark Rice
N4CMB