We could add two other shortcuts and keep < > (because a lot of people
like it and they are used to netscape).
Any suggestion ?

Why not also Ctrl+"<" and Ctrl+">" ?

Ok, my lastest suggestion is to use Ctrl+< for moving left, and Ctrl+>
alternatively Ctrl+Shift+< for moving right.
The drawback is that this requires two parallell shortcuts for moving
right which is tricky, but it's the best suggestion I can think of
right now that uses < and >.

Forget my last comment.
I think we should not use < > ...
I think using 2 accels is tricky and I'd prefer to not do it

Ctrl+< and Ctrl+> don't work here on a U.S. keyboard with the Dvorak
and qwerty layouts, since I need to hold down the Shift key to get the
angled braces.  I think Ctrl+[anything besides an uppercase or
lowercase letter or a number] shortcuts are going to have to be
translated for different locales, since we don't know whether Shift
will have to be depressed or not.  Is this possible?

Or what about if we change the "Next tab" item's accelerator to
Ctrl+Tab and "Previous tab"'s to Ctrl+Shift+Tab.  Are there any funky
keyboards where Shift+Tab has a special meaning?

This has the added feature of resolving
http://bugzilla.gnome.org/show_bug.cgi?id=52988 . :)

Tab is pretty standard AFAIK. However, you want to be careful not to
conflict with existing Tab conventions; ALT+TAB for switching windows,
TAB and SHIFT+TAB for cycling between widgets, and so on. I can't
remember anything off my head that uses CTRL+TAB and CTRL+SHIFT+TAB as
per your suggestion, though. However, with the plethora of window
managers out there, I would be surprised if there wasn't one that
doesn't also bind these shortcuts by default. But until someone
complains about that, I think your suggestion is an excellent one.

It doesn't look like this is a viable solution, unfortunately.  GTK
doesn't seem to allow the Tab key in accelerators.

Does anyone have other suggestions?

If GTK+ doesn't allow shortcut combinations using tab (like CTRL+TAB)
for tabs I think that should be considered a bug in GTK+, and reported
as such...

Looking at GTK's source, it appears that this is intentional.  GDK_Tab
is part of the "invalid_accelerator_vals" array. :)  I don't think
this is something that we can get changed.

We can ask the Usability Project about this problem.

It sounds like in GTK 2.0, Ctrl-PgUp/PgDown will go to the 
next/previous tab in GtkNotebooks:
http://developer.gnome.org/projects/gap/keynav/gtk_containers.html . 
Perhaps we should use those instead for the time being (they work
here).  Opinions?

i'd say "go for it"

Yes, please use that.

Okay, in CVS I've changed these to:

Previous tab: Ctrl + Page Up
Next tab: Ctrl + Page Down
Move tab left / right: Shift + Ctrl + Page Up
Move tab right / down: Shift + Ctrl + Page Down

Several caveats:

1. GTK calls the keys Prior and Next instead of Page Up and Page Down.
 This seems confusing to me, but I assume there are some keyboards
where this is what the keys are actually called. :)  In any case, I
don't think there's anything that can be done about this apart from
requesting a change in GTK.

2. I swapped the functions of Page Up and Page Down from GTK 2.0. 
This way makes a lot more sense to me, especially when you have a
vertical tab listing where the previous tab is above and the next tab
is below.  I'll probably file a request that it be this way in GTK 2.0
as well.

Closing for now; if there are any problems, please reopen.

*** Bug 60195 has been marked as a duplicate of this bug. ***

Regarding point 1 and the labeling of "Prior" and "Next" in gtk+. This
is reported as bug 63700.

Bug 67606 mentions an alternative set of shortcuts for switching tabs.