Undo doesn't work after diff

[Dan]

These are all nice features.  I can't promise how many I can do for 2018.

[Dan]

This happens in V21.0.3 as well as in beta 3.

Make a change to a buffer, right click on a file tab and select diff.  After the diff window opens, close it and do Ctrl-Z undo.  Slick moves the cursor to the bottom of the buffer and says "cursor movement undone".  Do ctrl-Z again and slick says "nothing to undo".

This feature has been added for 23.0.  I think it's in Beta 6, but it's definitely in RC 1.