When multiple buffers are open, Ctrl+Tab and
Shift+Ctrl+Tab are reversed. Ctrl+Tab moves to the
previous file, where it should move to the next file
like all other tabbed widgets.
I note that Rev 1.120 seemed to have a similar problem:
Fixed previous and next buffer commands and menu items
to always work
consistently. Previous, F6 means move to older.
I guess that something was changed internally, but
didn't go looking.
Attaching a trivial patch