onReleased is the only thing that clears the pull's pose, and a MouseArea
whose grab is taken away never gets one — it gets onCanceled, which had no
handler. So a cancelled climb left `dragging` true, the pull progress set and
the app posed at 0.6: shrunken, with nothing on screen to say why, and no way
back except pulling the pill again to force a fresh press and release
through.
Never a commit. A gesture nobody finished only has to put the glass back.
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