The font size in the
Font section changes as you choose different font sizes so that you can see what it looks like; to see the change in the rest of the application, you must log out, then log back in.
Also notice that one of the font size options is "Default". This selection causes the application to use the font size that is currently specified in the
workspaceCSS.xml file. By default, the font size in this file is set to "Small," but it is possible that that file has been modified.