bug#20182: 24.4.91; [GTK3] Vertical scroll bar is "indented" from right edge of frame

[N. Jackson]

At 13:16 -0300 on Tuesday 2015-03-24, Jan D. wrote:

>> 24 mar 2015 kl. 11:51 skrev martin rudalics <rudalics@gmx.at>:
>> 
>> > 16 was the hardcoded width for Gtk2.
>> 
>> Does that mean gtk_widget_style_get is broken for Gtk2?
>
> It means that the width it returns is 16.
>
>> 
>> > You can #ifdef it.
>> 
>> Like
>> 
>> #if (! GTK_CHECK_VERSION (3, 0, 0)
>>  if (w < 16) w = 16;
>> #endif
>> 
>
> Yes, or 
> #ifndef HAVE_GTK3
> ...
>
>       Jan D.

Of course, if gtk_widget_style_get() only returns 16 when the GDK
version is not GDK3, then this line

    if (w < 16) w = 16;

in update_theme_scrollbar_width() of gtkutil.c does nothing when the
GDK version is not GDK3.

Since we don't need this adjustment with GDK3 (with which
gtk_widget_style_get() returns the correct value from the toolkit), I
replaced the offending line with

    #ifndef HAVE_GTK3
        /*  if (w < 16) w = 16; */
        eassert (w == 16); 
    #endif 

and this seems to fix the bug for me. (Of course, removing the offending
line altogether has the same effect.)

I don't have a GTK2 system to test on, though.

Note: The badness is somehow encoded in my desktop file as well, so to
see that the fix was working I had to rename my desktop file or run with
emacs --no-desktop.