Window maximization does not work, keeps "unmaximized" size

Ever since I upgraded to version 0.46 (first the Jan. 8th development snapshot, and now the "preview" version), I've been experiencing a weird bug where

1. The program will start unmaximized, in a view that takes up the full vertical space and about a third (at the left side) of the horizontal space of my 1280x768 laptop
2. If I push the "maximize" button, the window will not change size at all, but look "maximized" (the borders are taken away, resulting in a little more screen space, and the "maximize" button will change to "unmaximize"). I can simulate a maximized window by resizing the window manually until it fills the screen, but it looks weird. First, my bottom panel covers the bottom of the default-size window, making it hard to resize vertically. Also, it's impossible to get the window to stretch all the way to the right of the screen, leaving a slight gap to the right when I "maximize" (not really) the window.

It certainly doesn't make the program unusable, but it is weird and a little annoying. It's frustrating 'cause it seems like it must be a simple problem, but hell if I can figure out what it is. By the way, I'm using Ubuntu 7.10 ("Gutsy Gibbon"), with the Metacity window manager (though I think this happened in Compiz, too, before ATI updated the fglrx driver and broke Compiz support for me, yarrr). I've got a Radeon Mobility 2300 HD, though I'm not sure if that's relevant (ph33r my LEET BUDGET HARDWARE). Aaaand, I've recently upgraded to the newest ("8.1") version of the closed-source fglrx driver, from "7.11", leapfrogging "7.12" because it wouldn't work with my--or practically any--laptop's resolution. (As I said, the new version broke Compiz for me, though. Leave it to ATI to know how to solve problems only while creating new ones.) The same problem occurred before, though; it all began when I upgraded to the Jan. 8th snapshot of Inkscape 0.46, from "0.45.1-1ubuntu5."

Comment if you want me to add any extra tests. I haven't read anything about this on the Intertubes, so I guess it must be a fairly rare bug... lucky me...