HiddenColumns markings and a column disappear switching from wrapped mode to normal

Load uniref50.fa and hide some columns right at the very end of the alignment. Switch to wrapped mode - hidden columns still shown - and then switch back. The hidden columns markings have disappeared, as has the last column of the alignment. You cannot scroll further to the right. Scroll left and right again, and the markings and missing column reappear.

A form of this seems to exist in 2.10.2b1: the blue triangle disappears but the blue line is present, and I think the last column does not disappear.