Can't press up to move the caret when there's a word wrapping

[sorawee]

Consider:

#lang racket


("aaaaaaaaaaaaaaaaaa" "bbbbbbbbbbbbbbbbbbb")


123

Paste this to the definition pane. Enable word wrapping. And resize the definition pane so that it looks exactly like this:

Now, place the caret at the last line, and repeatedly hit "Up" to move the caret toward the first line. It will get stuck in front of "bbbb.

Note that the width of the window must be just right to provoke the issue (with the ending " entering a newline). If the width is too small, the caret is able to moved just fine. If it's too large, it will work fine too.