There is yet another bug (and these are separate): the addition and deletion of spaces within a line are not detected/shown by Compare evisions. For example, if the original line is
let's have a virtual block partyand it is edited to
let's have a virtual block partythen Compare Revisions does not show the change and simply displays the original.
Therefore, when Compare Revisions shows no changes (no green text), it's possible that either (1) no change was made yet a revision was created anyway (as I first reported), or (2) the spacing was changed. For completeness's sake I have to say that of course there may be other bugs involving changes that don't show up, but I'm guessing those two are the extent of it.
For awhile, I had just one group, wherein the wiki was strictly controlled and only mods could change the pages. So these bugs never became apparent to me. But now that I have another group, wherein everyone can change wiki pages (and in fact is encouraged to do so), these wiki bugs are problematic (including the previously reported one of not controlling simultaneous editing).
Messages are the sole opinion of the author, especially the fishy ones.