This is probably an issue with curtsies, but until I'm sure I want to report it here first:

Steps to reproduce: Enter something like'間'.isalnum(), then move the cursor back (left arrow key) such thata is the next character, and insert anx.
Expected behavior: Visually it looks like we're about to insert anx betweenis andalnum. So I would expect the line to sayisxalnum.
Actual behavior: It now says'間'.isaxlnum(), with the next character seemingly being thex.

Try this out withy instead of間 to see the expected behavior.

I may have broken this in the patch to#703, I'm not sure.

The pun ("間" meaning "between") is entirely coincidental, but I like it, and I'm keeping it.