A frame hidden while a button was pressed on it still got OnMouseUp on the release, and its stale capture aimed the next chorded press at it. And showing any frame, even one that takes no mouse input, scheduled a hover re-pick, so a still cursor could fire OnEnter or OnLeave a tick early.
In the reference, the hide's input-index removal clears the capture slot when it holds the hidden frame, and the release goes only to the capture, so it reaches no one. The hover re-pick is armed only when a show inserts a frame into the mouse index.
The hide now drops the capture and the pressed frame; the release then runs nothing, no world click either. A show arms the re-pick only for a frame that takes the mouse.
Tests cover hides while pressed and shows with and without mouse input.
Fixes#844Fixes#845
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>