If colors were added to specific icons on the icon bar, it would make identifying the icon needed much quicker. For example, I would make DELETE the color red.
@kry if this aligns with what you're asking for, we can merge the threads (and votes) together to keep the conversation focused in one place. Just let me know 😃
I can imagine you want the interface to appear as clean as possible... Yet I fully agree with making the icons in color. You do have a nice blue button for a new message, but when multiple messages are open, seeing the colored icons across the top makes them easier to instantly access.