When Krita's Toolbars are in vertical mode (docked to either the left or right side of Krita's window), I must drag the handle until the cursor is outside the toolbar's perimeter to trigger the undocking.

This can be confusing on small, Hi-DPI displays. You see, Krita's "Brush and Stuff" toolbar, at its default arrangement, is VERY wide on this kind of screens, it can cause some unfortunate synergies.

Take Samsung Galaxy Tab S8 for example -- this device has an 11-inch screen with a resolution of 2560x1600. As a result of Hi-DPI adaptation, the "Brush and Stuff" toolbar takes up about 1/3 of the screen's width when docked to the left side of Krita's window. I was trying to drag the toolbar towards the right to undock it, but my initial attempts failed -- naturally, I only dragged the handle right-ward for the distance of an icon's width. 

I think dragging the distance of 1/3 of the screen to undock a toolbar is unreasonable (Even on a more favorable screen like Cintiq Pro 24, the experience was not good). Although now, I know I can drag upward to undock it easily, but at the time, I didn't want to dock it under the menu bar, so I avoided dragging upward. It took me quite a wild goose chase before I figured out what was happening, and I tend to think I wasn't alone with this exact situation.

Tested with:
Samsung Galaxy Tab S8 with One UI 5.0 (Android 13)
Krita 5.1.2 and Krita Next (2022-12-10)