[removed151214]

Well, have you ever... Removing all the .shortcuts you mentioned seems to have fixed it! I'll still answer your questions in case it might be helpful for anything else.

It is still useful, as it tells me what the problem was (even if not why it happened, as it were) - it looks like there was a problem with one of the submenus you edited (possibly Music, based on the position of the blank entry), which caused skin shortcuts to create a rogue menu entry without a visibility condition, hence why it showed up on all submenus.

Just in case it happens again, I'd recommended building your submenus one at a time - make the changes to that submenu, then go to the home page so that the menu can be built. If the rogue menu entry shows up again let me know which menu it was you had just edited, so we can track down the why of all of this and stop it happening in the future

No, thank YOU for your effort and help.

You're very welcome.