This use case is a bit niche, so I'm not sure if this is something on my end, or an undocumented change. I'm throwing this out there to see if anybody else can help test and report back.
I have a dual monitor setup. Both monitors are set to the same resolution, 1920 × 1200 I have them arranged so that my primary display is on the right, and the desktop extends to the left, like this:
In previous versions of OS X (at least Snow Leopard, possibly earlier), moving the cursor to the Apple menu with enough force would 'stick' it in that corner for a brief moment instead of immediately moving to the next display over. This was done, I believe, to preserve the ability to throw the cursor in the corner without needing to aim to hit a specific target. If you slowed down, you could easily move back and forth without hitting this little snag, and the cursor would keep moving if you kept moving the mouse, so it was an extra little exception case that had to be programmed in.
After upgrading to Lion, this no longer seems to work. I've not changed any settings, and disabled any third party tweaks that might interfere. Still, it seems weird that such a strange edge case would be specifically removed, so I'm wondering if anybody else can confirm/reproduce this behavior? If you've got dual displays and wouldn't mind testing it out real quick and reporting back whether it works or not and what OS you're on, that will help narrow down what's going on.
As a side note, I know that I can rearrange the displays in the Arrangement tab to have the left one 'sit' a bit lower, which will give me a corner to aim for, but this is non-ideal since then windows will look pretty funky when they span it, as I don't want to have to physically re-arrange the screens.
In addition to testing this out, if anybody has a link/source that documents this behavior for either OS, I'd appreciate it.