Hello Laszlo,
Thank you for writing.
I have tested the property mentioned and it seems to be working just fine on my end - see attached video (opens in browser). Setting the Font to the TextPrimitive is also an option. Feel free to use it, but can I please ask you for more details about the case you experience issue with the control property, so I can make sure everything is OK with the control.
Thank you in advance for your time and cooperation.
Regards,
Stefan
Telerik