Protected spaces are being removed automatically, when saving

this can be reproduced in 2 different scenarios:

1. open a segment, that contains already a non-breaking space. Change something in the segment without touching the non-breaking  space. Save it. Result: The non-breaking  space will be gone after saving.
2. open a segment, that will have a match from the TM, that contains a non-breaking space. Take over this match to the segment. Save the segment. Result: The non-breaking space will be gone from the segment after saving.