This is something I put together quite quickly for you. I just extracted the interface window from
MsgPlusLiveRes.dll.
To use it, go to
Plus! > FormatPanel > Show.
When you press a button, it will debug trace the button's name. Note that the colour buttons are named after the colour number! (For example,
BtnColor23 results in
[c=23][/c].)
I'm not sure if there's any other way to do this, so you might have to recreate the window.