bug#18990: 25.0.50; Scroll bar display problems

[martin rudalics <rudalics@gmx.at>]

 > This is not what I observe: I have no setting for the scroll bar in a
 > Gtk config file, but when I start emacs with -Q --eval
 > "(modify-all-frames-parameters '((scroll-bar-width . 7)))", then the
 > scroll bar is displayed thin on the right, unlike when I make it be on
 > the left, and the right fringe is not overlaid by the scroll bar like the
 > left fringe is; see the attached screen shot.  The thin scroll bar looks
 > crappy and clearly is not being properly modified as a toolkit widget,

In the attached screenshot the left scroll bar is displayed in its
default width (you didn't tell us that value so far) partially
overlaying the left fringe of the window on the right.  The right scroll
bar is cropped at the external border (by the window manager).

 > but just as clearly Emacs is able to modify it.

You mean that Emacs can move the slider?

 > I guess the easiest
 > solution would be to make modifying the Gtk scroll bar a noop.

The width and the height, yes.  The position can be modified without
problems.

 > I hadn't noticed this before, but the attached screen shot confirms it.
 > Interestingly, the right fringe of the left window is not hidden.

Emacs tells Gtk where to put it.  Make `scroll-bar-width' very wide and
you should be able to see how Gtk reacts.

 > Do you mean that the above invocation should also make the horizontal
 > scroll bar thinner?

No.  The corresponding frame parameter is called `scroll-bar-height'.
Some systems allow different values for height and width of scroll bars.

 >(Does it with the Lucid build?)  If so, then I can
 > confirm that it isn't thinner for me; but I haven't seen any display
 > glitches either with the horizontal scroll bar like I have with the
 > vertical scroll bar on the left.

I think you need Xaw3d support for Lucid scroll bars.  Both Lucid and
Motif scroll bars can be arbitrarily resized here.

martin