Problem with data-iconpos="notext"

Problem with data-iconpos="notext"

I have a toolbar with some buttons in it. They are vertically centered when there is text next to them, but when I put in the attribute  data-iconpos = "notext" the button is no longer centered vertically. I know I can manually change the CSS, but before I did I wanted to check to see if this was intended or not.

Here is a fiddle to show what I am seeing.