bug#8530: 23.2; Button 'mouse-face property loses Bold and Italic properties

[Chong Yidong]

Eli Zaretskii <eliz@gnu.org> writes:

> the font is explicitly ignored, at least in my reading of the code.
> Maybe that's because mouse-face was intended to _highlight_ the text,
> not redraw it in some entirely different face.  Or maybe there are
> other reasons, or even no particular reason at all.

Here is one reason:

- Move the mouse cursor over some text with a mouse face.
- Mouse face activates.
- Mouse face has a smaller font, so the text shrinks in size.
- The text is no longer under the mouse cursor.
- Mouse face should not be active.
- ????

I have added a note to the Lisp manual that the mouse-face can't be used
to change the text size.