Not sure if this has been suggested yet, or if it's even possible to do, but...

Wouldn't it be nice to be able to undo your brushstroke while it was still loading?
This would be really helpful when using really big brushes on big canvases. Currently you have to wait until the brushstroke finishes to undo and on bigger projects that could take quite some time. The new "instant preview" option really speeds up the process, but it's only a preview, you still have to wait for the actual brush stroke to load in the background to be able to undo it.
I'm not tech savvy enough to know how hard or even possible adding such option would be, but I know that it would really improve the painting experience of Krita.

What do you guys think?

Hey M.Shaw,

Yes, it's a known issue https://bugs.kde.org/show_bug.cgi?id=363311 ; I reported this one during the beta version of 3.0. It was 'confirmed' but the development team is still studying the good way to perform the cancel of this stroke. It's a bit difficult and problematic :
- It's not possible to undo an action not completely 'done'
- Undo key could 'cancel' maybe, but it would break the history of stroke/action and make 'redo' impossible, then opening a new bug.
Do you think the stroke should be fully cancelled ?
Here I think no, I think the undo action ( in this case ) should be 'queued' after the rendering finish.
It means it will freeze a bit the canvas to prevent user adding a new painting stroke, then when the rendering is finish, perform the 'undo' action ( totally reversible this time.