Fix width tabs

[Matthias Meulien <orontee@gmail.com>]

When a tab has multiple windows, its name is updated depending on
current buffer name.  Switching window (C-x o) results in the tab being
renamed.

But buffer names of a given tab have heterogeneous lengths (*Help*,
*Summary Listes/emacs-devel*, etc.). Thus the tab bar layout may change
a lot while switching window, which is annoying: Visually, the tab bar
can occupy two lines then one, etc.

I'd like to configure all tabs to have the same width, whatever the
length of the name of the current buffer of a particular tab is. That
width could be the frame width divided by the number of tabs.

But I've not found a way to do that with current options. Is it already
possible?

My understanding is that it's the default behavior in other applications
like Firefox. Is there good reason to have different default?
-- 
Matthias