So, version 1.1 is out. Now assignments to the "condensed" font are actually honored. I also played around with the buttons on the details page, I hope they all keep showing now (still, no guarantee. If you set some huge font as the sans serif one, then the "condensed" button may still be moved to the next line).
I came to the conclusion that the "blank text" issue simply cannot be fixed.
Helvetica seems to be a font where this is notoriously happening. Bad luck
A reboot does seem to help (sometimes).
Anyway, downloads are available in the updated first post of this thread.