Double-click to select text is broken

- For a terminal which is not capturing mouse input
- When the user clicks and drags, it triggers our special drag-and-drop behavior which works great
- But when the user double-clicks, it triggers some underlying text-selection (not ours). It doesn't look like the text selection above, and `Cmd+C` doesn't do a copy of the selected text

No file or test is named. Start by reproducing the double-click in a terminal that is not capturing mouse input, then trace the mouse handling and text-selection path involved in the drag-and-drop behavior. Done means double-click selection matches the intended selection behavior and Cmd+C copies the selected text.

Written by the indexing model from the issue text.