Stuart,
The reason why the text is cut-off or wrapped on a second line is most likely because all the text labels that you see in PlanetPress are placed inside of "label" boxes. And these have a fixed width, so when the font scaling is increased in Windows, it's unaware of it, and so it will either cut off the text, or wrap it on a second line, since it exceeds the label's width.
It would be nice if the label properly scaled, but I'm not certain if it can easily be done, and furthermore, it might require a redesign of the user-interface to accomodate the possibility of fonts scaling(so that you don't end up with text overlapping due to a label being too long, for example...). Considering this problem has always been there in all versions of the software, and since there has been very little complaints about it over the years, I wouldn't bet on it being fixed in the near future.
Regards,
Raphaël Lalonde Lefebvre