In-place editing of numeric properties (on various panels)

[Sz.]

Most (all?) of those values can be adjusted by dragging up/down, but sometimes it could be faster and/or more precise to just enter a value directly. Which is also possible, but now it requires a double-click to open an extra window displaying just the same value, but in an editable form, and then another click on the value field to actually get the cursor. Only then can the value be edited, after which another click is required for closing the edit window.

This should be simplified to just a single click into the property widget and editing the value there, in-place, saving it by clicking elsewhere.
(Note: cancelling the change should be available via Undo, consistently.)