Text selection highlight for copying messages is not cleared when clicking and releasing without dragging #1992

There is a sporadic issue that sometimes happens when running opencode in tmux, where clicking on message text and releasing without dragging causes the user to be stuck in a text selection state. Moving the mouse around in this state causes text to be highlighted even though mouse is not held down. Clicking clears the highlight (without copying text) but moving the mouse will create a new highlight. The user can only get out of this state by successfully triggering a copy by clicking and dragging. Accidentally clicking anywhere in the messages causes the issue again.

This is an odd bug because I've only observed it in tmux sessions, but creating a fresh tmux session does not have this issue. However, once the issue presents (trigger unknown), it happens across all panes in that tmux session and persists even after detaching/reattaching to that same session.