Created attachment 101391 [details] warning At times Krita locks up. I can't draw or do anything else. Trying to save gives me a warning "Waiting for image operation to complete". The button "Cancel Operation and Save" does not work. There is no apparent operation going on and the only way I can get back to normal is to quit and not save, potentially losing a lot of work. It usually happens after I've switched workspaces and it happens both in Unity (Ubuntu 14.04) and Moksha (Bodhi linux) desktop environments. (Two different machines)
Can you try with 3.0.1.1 and 3.0.1.90, too? I haven't seen this happen before, but I seem to remember that we've had similar reports from Unity users.
We've had other reports about Krita hanging when switching workspaces, too, but we found a workaround which is in 3.0.1.90. Please try that version or the latest beta which we'll release today or tomorrow. If you can still reproduce the issue with those releases, please re-open the bug.
Have been trying 3.0.1.90 and have not had this issue with that version. Thank you!