if you are running plasma and funky things start happening with the display of things, such as windows getting chunks bitten out of them when a plasma tooltip or drop down appears or the panel stops updated when running a composited window manager, i'm both sorry and hopeful.
i'm sorry because i feel your pain. i'm sorry doubly so because there's not much the plasma team can do about it inside of plasma itself. if you're wondering why i've closed your rendering bug as "invalid" on b.k.o (even with the explanation provided when doing so), here's some more insight into the matter:
while i'm sorry, i'm also hopeful because by sticking with it and continuing to not back down on using facilities that are supposed to work in theory, such as applications using argb surfaces, we're giving the kind of test cases, not to motivation, that the people working on x.org both in the core as well as on drivers need.
until apps start pushing and pulling on these features it'll be really hard for the fixes to be arrived at; which creates a sort of vicious circle, as one of the kde/x.org hybrid hackers pointed out tonight on irc: without apps, things don't get fixed; but if things don't get fixed, people are afraid to write apps using these things. everyone points fingers at everyone else and we're at a stand-off where several years after the initial kdrive experiments that made us drool over the possibility that one day we might have a composited desktop experience and quite a bit of time since compiz debuted things still suck in argb and composite land.
we're going to help break that vicious cycle by taking a deep breath and plunging forward, exposing issues as we go. they aren't easy issues either: some of the window interaction that leads to issues where argb windows take bites out of other windows (argb and "normal" alike, are apparently rather non-trivial to get right.
best of all: i'm confident that this just theory about breaking cycles. nVidia released a new driver at the end of december that fixes numerous rendering issues people were seeing when using their drivers on nVidia hardware. the fix was specifically in reaction to the issues plasma was having that had been there for some time but which were just never exposed clearly before. so that's awesome, and i'm really impressed with nVidia on that one.
but we have a lot more to get fixed, and honestly i'm not the guy to fix these issues. i can only help expose them and provide clear test cases. in the meantime we'll have the occasional rocky moment as we discover together the various leaks in the hull of x.org and its drivers. but it's the only way to get them patched up. i hope you'll understand and support us as we go; in the end we'll eventually get to flawlessland together and everyone will benefit, not just KDE. =)
p.s. if you're wondering what cashews (in the title) have to do with anything, look at the desktop toolbox in the upper right hand corner of your screen. ;) mmmm.. cashews.