You must have Opus set not to show Hidden files/folders.
If you want them shown all the time then go through all of your Folder Formats and make sure they do not have the H checkbox set under Filters / Hide Filter (see below).
If you only want to see the hidden items temporarily, hiding them normally, then you can make a toolbar button or hotkey which runs this command:
Set HIDEFILTERATTR=h(That command will act as a toggle automatically.)
