I added a text box to a GIMP project in a new layer. I can select it and a panel shows up with the text properties (here it's out of the main image, but there is text in it):
But when I change the font size in the top right, the text's size doesn't change. If I hit enter, nothing happens. When I leave the panel (with escape or by selecting something else), then open that panel again, the font size goes back to the original value.
What am I doing wrong? How to validate my input so the font size actually changes?