There are 2 ways to do this.
1. If you change the width from Fixed to Automatic, see screenshot, then you can change the other text sizes.
2. Change the fixed width to a size that accommodates the Zone Name at the font size you want.
IMHO this is a bug as text will not wrap to keep the font and stamp sizes you want.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"