I assume the B, I, and U toolbar buttons are meant to make novices feel all warm and fuzzy, but to a professional they're extraneous and even confusing. For instance, I just created a text box using a font that has many weights, and selected the Black weight. Mysteriously, the program automatically highlighted the "B" button in the toolbar. I figured this was a bug, so I clicked on the "B" to unselect it, and it selected the Light version of my font. Then I clicked the "B" button again to undo what I had just done, and the program selected the Bold version of my font. None of this behavior is at all what I wanted or expected. If you want pro users to take you seriously, you should grant that they have the wisdom enough to know how to use bold versions of their fonts.
I recommend you get rid of the B, I, and U toolbar buttons.