> I notice that going from lyx 1.5.7 to 1.6.1 the keyboard shortcut > "Alt+C B" has changed from \mathbf to \boldsymbol. This means, for > instance, that latin characters become bold italic rather than just > bold.
This is correct. Latin letters are in formulas by default italic. So when you make an italic letter bold, it becomes of course bold italic.
We also provide a shortcut for \mathbf, see the shortcuts section of LyX's preferences. You can there also change the existing shortcuts or define new ones.
regards Uwe