Description of problem:
It may be that this is the fault of the Ardour lot, but look at the screenshot. The text in the "location marker" bit has gone mad.

It was fine in F9.

Now, people in Ardour land tell me they use the same version without trouble on different distros.

Also, there is font scaling in Ardour, it has a slider in the settings, but this doesn't seem to affect the ones in the location marker bit.

I'll file a report with Ardour in their Mantis thing as well.