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

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 20 Apr 2011 21:28:39 -0700
> From: PJ Weisberg <pj@irregularexpressions.net>
> 
> (defun buggy-button()
>   (interactive)
>   (insert-text-button "MyButton"
> 		      'face 'font-lock-function-name-face
> 		      'mouse-face 'font-lock-warning-face))
> 
> Evaluate that, then call buggy-button to insert a button.
> 
> font-lock-function-name-face is blue
> font-lock-warning-face is red/bold
> 
> The button that was inserted has a blue face, but when you hold the
> mouse over it it turns red, but not bold.
> 
> The manual says that mouse-face is "merged with the usual button face",
> so I expected this:
> 
> (defun buggy-button()
>   (interactive)
>   (insert-text-button "MyButton"
> 		      'face 'font-lock-function-name-face
> 		      'mouse-face 'bold-italic))
> 
> To result in a button that is blue, bold, and italic when the mouse is
> over it.  Instead, I get a button that goes back to the default face
> when the mouse is over it.

Well, "merged with the usual button face" for some value of "merge"...
We never use any information from the mouse-face except its colors.
So we currently don't support bold and italic attributes in that face;
they are simply ignored.

We could close this bug report, or we could leave it open as a
wishlist.