Created attachment 136573 [details] screen shot of tabs covering up icons using mac osx sierra and libre office vanila from the apple app store - when opening multiple documents there is a tab bar titled with the document title - this tab bar covers the tool bar so you can't click on icons! If you notice the screen shot included the arrow shows the tab of the third document oppened for editing and how it covers the icons below it.
Yup, we don’t support the MDI mode yet. *** This bug has been marked as a duplicate of bug 103486 ***