Created attachment 105096 [details] Screenshot showing the cursor block (scrolled down while mouse was on bug-list above) When rendering the screen, a block of pixels maybe 64x64 (might be 32x32 up-scaled, hard to tell with the high-res screen) around the mouse cursor does not update in response to scrolling, content changes (e.g.typing text where you click, buttons doing click animations), etc. I can scroll quite a way and then leave the cursor sitting with an out-of-sync content background for a long period (at least 15s) without the background being updated to match the current background. If I move the mouse after the background freezes, the background seems to be selectively updating in the direction I move, which looks like a cache-invalidation update that's taking the position and motion and only updating that part of the cursor-box that should be getting changed. Platform: Dell XPS 9550 (Early 2016) Graphics: GeForce GTX 960M OS: Kubuntu 17.04 (up to date)
The window manager is not responsible for rendering the mouse cursor. This is either a bug in the X server or the nvidia driver.
I've installed the newest nvidia drivers and I faced the same problem. It seams that there is problem with composite. After switching to XRender there is no problem but. With OpenGL (2.0 and 3.1) i have problem like on the screenshot. nvidia drivers 381.22 (the same problem with 375.x) kernel 4.10.0-24-generic xserver 1:7.7+16ubuntu3 I have nvidia-prime Grafic cards: GM107M [GeForce GTX 960M] (rev a2) Intel Corporation HD Graphics 530 (rev 06)