Peers are UPs. I forget in which LimeWire version (and the feature history doesn't seem to have it), but the Connections tab was changed to have a few different words.

Peer describes a connection from an Ultrapeer to an Ultrapeer.
Ultrapeer describes a connection from a Leaf to an Ultrapeer.
Leaf describes a connection from an Ultrapeer to a Leaf.

This is so that we can easily spot cases where a connection was established one way, but the status of the LimeWire changes. It would be very bad, for instance, if a LimeWire had an ultrapeer connection and then became an ultrapeer itself.

Re: GUI corruption -- that's not good at all. On all tabs? That's really not good. Nothing significant changed. Were you also using Java 1.5.0_01 when running 4.3.2? What happens if you click to resize the program?

Re: screensaver. -- We'll look into that.

Re: both GUI corruption & screensaver -- Do you have the most recent video drivers for your graphics card?