There's a small bug with the [Default Font] & [Size] dropdowns in Firefox. Steps:

1) Highlight some text on the editor. 

2) Click on [Default Font], and change the font to a different font. 

3) Notice that the font in the selection has changed, but the font shown in the (now collapsed) [Default Font] box is... Default Font. 

4) Click elsewhere (not within the selected text), and then click somewhere within the previously selected text. 

5) Notice that the font shown in [Default Font] is correct. 

 

 

Any ideas how I can solve this?