Keyboard navigation does not move word highlight

When I click anywhere in the editor with a pointer device, the caret is positioned where I click and the closest word is highlighted.

When I navigate using the keyboard, e.g. cursor keys, ctrl-cursor keys, etc., the word highlight does not follow the cursor.

(This might be intentional, but it confused me for a second.)

Reproduce the issue in the editor by clicking near a word, then moving the caret with cursor and Ctrl-cursor keys. Trace the editor's caret movement and word-highlight handling to determine whether the highlight should follow keyboard navigation, and verify that the behavior is consistent after the change.

Written by the indexing model from the issue text.