Firstly, a rant: as of December 2007, a self-righteous idiot named Chris Cunningham thinks he can change the name of "Fitts' law" to "Fitts's law" on wikipedia, in the name of grammar. To boot, he claims to have changed every link to "GNU/Linux" to point to "Linux", probably without regard to the difference in meaning. I am not happy. Fortunately, a recent attempt to become an admin was unsuccessful.
I noticed recently in Epiphany that I couldn't hit the scrollbar by slamming the mouse to the right edge of the screen. It turns out there are two bugs stopping me doing this, one less subtle than the other.
The less subtle one is that a recent commit to the ati driver turns on VGA output in my graphics card (even if there's no external monitor attached), and for obscure reasons this results in the virtual screen size being a little bit wider than 1024px. Fixes include "xrandr --output VGA-0 --off", or editing xorg.conf to disable that output monitor.
The more subtle one is actually a bug in Epiphany (or at least in GtkNotebook). With just one page open, using the rightmost pixel works fine; but as soon as you need tabs at the top, there's a two-pixel border stopping you.
Just another niggling desktop annoyance.