The brush did nothing, and neither did three other things nobody had tried
lately: clicking a subject on the photograph to select it, placing a repair,
and sampling a neutral. All four are TouchAreas over the canvas, and all four
sat behind the pan/zoom area, which is full-canvas and enabled for everything
but a crop. It took every press in the viewport and they were never offered
one.
Slint hit-tests siblings front-to-back (`send_mouse_event_to_item` visits
children `TraversalOrder::FrontToBack`), a TouchArea answers `GrabMouse` on any
press it is enabled for, and the first grab aborts the traversal. Front means
*last declared*. Each of the four carried a comment saying it sat "above the
pan/zoom area so a click reaches it first" — true of the order they were
written in, and backwards.
Nothing about the geometry decides this, so nothing about the geometry could
have fixed it. The pan area is declared first now, as the backstop it always
meant to be, and the rule it leaves behind is that the general case goes above
the specific ones. `GradientHandles` is the other end of that rule and is why
dragging a handle has worked all along while everything between it and the pan
area did not.
The order is asserted in a test, because this is a fault that compiles, passes
every other test, and silently removes four tools at once.
dtourolle
5d175cc668