It sure feels that way! Yosemite is the worst OS release in years (in terms of stability). I don’t really care the the visual changes either, but I have to develop on Yosemite, so that my apps work correctly on it.
This is kinda interesting. After updating to the release version of 10.10.3 today, the problem in my test app is somewhat better, and different than it was under 10.10.2.
I can still get it to flicker, especially when the drag goes over the bounds of the picture that’s drawn under the group2D. But, it happens less easily, and it also doesn’t seem to get progressively worse once it starts. It flickers a bit, and then calms down again until the next flicker.
It’s still ugly, but a lot better than it was…