Currently Being ModeratedNov 1, 2013 2:27 PM (in response to Don Harris)
The only way to make the menu bar bigger is to change the resolution of the screen. The article below will assist even though it says it is for OS X Mountain Lion, the steps are the exact same. You can Change how big the icons of the folders in Mail by going to System Preferences > General and change the Sidebar icon Size.
Currently Being ModeratedNov 14, 2013 2:02 PM (in response to norm123)
Changing the screen resolution isn't an option for me. I want it to stay the way it is.
I upgraded from 10.7 to 10.9, and this is the first time I can't change that sidebar text in Mail, which is frustrating. You used to be able to change it in the Fonts & Colors preference pane.
It also frustrates me that Mail didn't import my rules. I had dozens that I developed over years, and now they are gone. Sometimes Apple just doesn't care how much trouble they cause their users.