I can't change the font size manually

[LaserBabes]

Suddenly I can't change the font size anymore, only the suggested sizes work, but for example I can't change
it in 15 mm. I hope somebody can help me. I have already closed the programm but this didn't work. I hope somebody can help me. Kind regards Ellen 
i

[Monika Gause]

So you are entering the value in the text size field and then what happens?