I confirm the issue with italian locale.

Does this issue still remain if you decrease the padding from 16 to 2 (or something like that) of the take_picture button in Glade (under Button Properties > Packing)?

Apparently it doesn't :) I didn't notice there was a minimum size hardcoded for the drawing area. It would still happen if I could size down the window a bit more, but I can't. Anyway it's there again if I set my font size e.g. to 12 or if I set a wider font. That's the drawback of hardcoding sizes, you can never find one that fits each case.

commit e3dfe574aa1b37231dbc1a91b25b5374fb2e2a32
Author: Filippo Argiolas <filippo.argiolas@gmail.com>
Date:   Tue Jun 16 16:01:32 2009 +0200

    ui: remove padding from the take_picture button
    
    Use alignment xscale property instead of padding in the take_picture
    button. Doesn't fix but at least partly works around bug #573301 (the
    button can now grow up and fill the whole free space with no padding
    constraint).

Still far from a real solution at least now the button can fill up all the empty space with the only constraint of being centered in the toolbar. The bug is still triggered depending on the particular locale and font sizes so it's not fixed yet. IMHO the only solution is to completely get rid either of the label or the centered layout or just hard code a big enough minimum size which I really wouldn't like.

Probably things will be a little better if I'll write the custom widget for the toggle buttons (there will be more space for the button to grow in). [http://www.gnome.org/~fargiolas/toggle-button-mockup.png]

Shouldn't this bug be closed now? I tried the 2.28's cheese, and I don't see any problem now, so I think it's resolved… or does it depend of the locale?

Unfortunately not, it's still there unchanged...
Step to reproduce:
- switch to a locale where "Take photo" translation has a different length than "Start Recording" or "Take a burst" (e.g. LC_ALL=fr_FR.UTF-8 cheese)
- in Photo mode shrink the window to its minimum width
- switch to Video or Burst Mode
- see the window size changing

this only happens when you shrink the window from the default size to something smaller. 

should i close it?

Closing this bug report as no further information has been provided. Please feel free to reopen this bug if you can provide the information asked for.
Thanks!

the same problem here
on terminal:
(cheese:30192): Gtk-WARNING **: Theme parsing error: cheese.css:7:35: The style property GtkScrollbar:min-slider-length is deprecated and shouldn't be used anymore. It will be removed in a future version

cheese has alo of black space around of the display

the same problem here
on terminal:
(cheese:30192): Gtk-WARNING **: Theme parsing error: cheese.css:7:35: The style property GtkScrollbar:min-slider-length is deprecated and shouldn't be used anymore. It will be removed in a future version

cheese has alo of black space around of the display