Controls and the fields they affect are often far apart. Look at
the General tab's "Text font: <font> [Change]" function,
and the Code Assist tab's "Background for completion... [color]"
function. Now compare those to the General tab's
"Appearance color options, Color: [color]" function. The latter is
much easier to use.
This is UI subtlety, but I guess we could raise this issue upstream if
concerned about it. I'm not sure if this specific case (CDT editor
preferences dialog) follows the UI guidelines set by eclipse.org or not.
This is no longer applicable to the current version of Eclipse. The fields have
been totally re-designed.