On the kolourpaint that ships with Plasma 5: - When you zoom in, it zooms in on where your mouse cursor is, moves that point to the center of the work area, and moves the cursor there. - When you zoom out, it moves the location where your mouse cursor is to the center of work area (as best it can based on window size relative to image size) along with your cursor. On the kolourpaint that ships with Plasma 6: - When you zoom in, it zooms in on where your mouse cursor is and moves that point to the center of the work area, but leaves your cursor where it is relative to the entire screen. - When you zoom out, it moves the location where your mouse cursor is to the center of work area (as best it can based on window size relative to image size), but leaves your cursor where it is relative to the entire screen. Even aside from the fact that this a change in behavior (which is always annoying), this behavior change makes no sense - it's a 'dis-improvement' that makes pixel-level editing much more difficult.