bug#4147: 23.1.50: Info-search command strange behaviour

[martin rudalics <rudalics@gmx.at>]

 > It seems very easy to put the contents of the header line in a separate
 > buffer.  Do you intend to display that buffer using some mechanism other
 > than the header line?  I'm afraid this won't work for tabbar.el that relies
 > on the header line.

I never looked at tabbar.el so I can't tell.  But suppose you can make
it work that whatever it displays via `header-line-format' goes to a
separate buffer - and obviously relays back any user input on that
buffer's contents to the tabbar dispatcher which is the harder part.
Then we could display that buffer in a window attached to some other
window including a frame's root window.  That way tabbar wouldn't
interfere any more with other modes using the header line like info or
ruler-mode.  Also, tabs could be displayed on the left or right of a
window.

Moreover, users could choose between a one-tabbar-per-frame and a
one-tabbar-per-window setting.  In the former case the tabbar would
vanish only when tabbars are switched off or the frame gets deleted,
just like the toolbar.  In the latter case, a tabbar would disappear
whenever the associated window gets deleted.

martin