I have noticed that sometimes Confluence menus conflict with macros on Confluence pages.
For example, when I have a composition macro on the page and use the deck macro in it, the Browse menu disappears after the first couple of menu items. If I click Browse, I can see Pages, Blogs and half of labels...seems like the rest of the menu is somehow behind the rest of the page.
On another page, I use a Panel macro at the top of the page. When I save, the Tools menu becomes inactive when it overlaps the panel macro. So, I can select the first few items on the menu (Attachments through Restrictions). The rest of the items are visible, but I can't select them.