Re: vc-set-mode-line-busy-indicator

[Richard Stallman]

    Yes. mode-line-highlight (as now) for things you might click, which are
    highlighted as buttons on mouse-over. mode-line-emphasis for
    "non-interactive" things you don't click, which are always highlighted.

1. Do we really need both?  (I am worried about face bloat.)

2. If we need both, the name of the one for buttons should be
`mode-line-button' and the one for emphasis should be
`mode-line-highlight'.

3. Can we make the one for buttons by means of `button'
instead of having a separate face only for mode line buttons?