In the 3/10 and latest beta's I'm finding that it's no longer tab completing for $identifiers or %variables.
/set %foobar 12345
/editbox test $sha1(abc) %foobar $chan $me $isadmin $ctime abcdefghijklmnopqrstuvwxyz
When trying to tab-complete each of these identifiers, the cursor jumps to where the end of the evaluated result should be without actually hot-swapping the new string. i.e. tab-completing $ctime moves the cursor between the 'c' and 'd' because that's where the 10-digit time value would end if it began where the $ is. Same thing happens with tab-completing the variable, where the cursor position varies depending on the length of the variable.
This happens with /remote off too, so the culprit isn't an "on TABCOMP" event.