[oXygen-user] Insert empty elements using the elements view

Hi all, i have a question concerning the elements-view in Oxygen 9.1. I want to insert empty elements like <lb/> <cb/> etc. The elements-view lists <lb> among the elements which accoring to my schema are allowed at the current cursor position, but when i double-click <lb> it inserts the following fragment: <lb>lb</lb> "lb" being highlighted for editing. I checked the preferences but i cannot find any definition of the <lb> element. Where can I change such a behaviour? Any hints and pointers to documentation or solutions will be appreciated. Thanks, Philipp