If selected, a TAB command will be automatically done after the X
command. The X command will Mark all unread articles that have not been selected as read, redo screen to reflect changes
and put index at the first thread to begin reading. Pressing 'X' again will toggle back to the way it was before.
The '~' command will clear the toggle effect and undo all selections on all articles. It clears the
toggle effect of 'X' command. Thus after first doing a 'X', one can then do '~' to reset
articles. Thus, one can iteratively whittle down uninteresting threads.
