bug#25: frame parameter menu-bar-lines changes height of frame

[martin rudalics]

> I gather that `frame-inhibit-implied-resize' is a user option.  It's
> great that users can now control the behavior, but I wonder how that
> helps code and how it fixes the bug reported here.

Please refrain from calling this a bug.  It's a behavior you dislike and
we can try to modify it in your sense.  But let's do that in a minimally
invasive fashion so other users don't get annoyed by our modifications.

> The point of
> this bug was that `menu-bar-lines' should behave like `tool-bar-lines'
> does: adding or removing a menu bar, or increasing/decreasing the
> number of its lines, should not change the visible frame height.

For graphical displays now the following hold:

If a user adds both `menu-bar-lines' and `tool-bar-lines' to
`frame-inhibit-implied-resize' or the latter is t or the frame is either
maximized or fullscreen, then toggling either `menu-bar-mode' or
`tool-bar-mode' conceptually do not change the visible frame height.

If neither `menu-bar-lines' and `tool-bar-lines' are members of
`frame-inhibit-implied-resize' and the latter is not t and the frame is
neither maximized nor fullscreen, then toggling either `menu-bar-mode'
or `tool-bar-mode' conceptually do change the visible frame height.

And this holds for Gtk just as for Windows.

> If that behavior is only optional, and decided by users, then it
> sounds like things are not the same as for `tool-bar-lines' and
> that code cannot depend on the behavior being the same.

Code can always read the value of `frame-inhibit-implied-resize' as well
as the maximized/fullscreen status of a frame.

martin