Text editors

Hi,
    I find that if I press space button in the front of a paragraph( or a line) I will get normal empty spaces in Moodle 1.5. But now, in Moodle 1.6+, doing the same way, I will get some   rather than some normal empty spaces. Is it normal?
    I met some problems when I append a multianswer question. The non-breaking space &nbsp will cause the action above to fail and make the question empty.  This really puzzles me. Joseph told me that it is the non-breaking space that makes the function html_entity_decode() fail. In fact, he has reported it as Bug#6068.  But I wonder why we can press the space button and don't get non-breaking space in Moodle 1.5. Any suggestion will be appreciated.                                               Alexander.