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Gimp unstable development releases of 2.7 comes built-in single window mode (can be disabled), but I find it unstable at times. So I prefer the stable Gimp 2.6, especially since there are so many goodies you can use to enhance it, like GIMP Painter and GIMP Paint Studio, G'MIC or the GIMP Plugin Registry package.

So if you want to use the stable GIMP 2.6.x (tested with GIMP 2.6.11 under Ubuntu 11.04) and still get a single-window mode in GIMP, here's how to do it using a script called GIMPBox.

Before proceeding, there are a few issues that occur when using GIMPBox that you should know about:

• when launching GIMPBox, there is a slight delay (probably 1-2 seconds) when GIMP is not running as single-window. But like I said, the delay is very small;
• If you use Unity and AppMenu (Global Menu) is enabled, the GIMP menu won't show up on the top panel. You can still access the menu by right clicking inside the GIMP window or by running GIMPBox with a special command (see below) which will make the menu to show up in GIMP (but it's not possible to get the menu to show up on the top panel) like in my screenshot.
• You can't open multiple images by right clicking an image and selecting to open it with GIMP.
• By default, the keyboard shortcuts won't work. However, there is a way around this: you can press TAB and then you should be able to use the keyboard shortcuts. This is only required once for a session, but if you edit multiple images in the same time and keep switching between them, you'll have to press TAB again to use keyboard shortcuts.
• It doesn't work with GNOME3

If you are ok with these issue and want to use GIMPBox, let's proceed.

GIMPBox: single-window mode for GIMP (stable - 2.6.x)

1. Install the GIMPBox script.
If you want to take a look at the script, download it from HERE. For easier installation, copy/paste the commands below in a terminal:

2. Edit the GIMP shortcut to run the GIMPBox script instead of GIMP.

Search for "Main Menu" in Dash or for the classic GNOME desktop, right click the menu and select "Edit Menus". Then, under "Graphics" select "GIMP Image Editor", click Properties and:

a) If you don't use Unity with AppMenu (global menu), replace "gimp-2.6 %U" with "gimpbox %U":

b) If you use Unity with AppMenu (global menu) enabled, replace "gimp-2.6 %U" with "env UBUNTU_MENUPROXY= gimpbox %U" (yes, there's a space after "="):

The special shortcut for those who use AppMenu is required because using GIMPBox, the AppMenu won't work. Using "UBUNTU_MENUPROXY= " will disable the AppMenu for GIMPBox so the menu will be displayed inside the window, like in my screenshot.

If you want to edit the system-wide GIMP shortcut, open a terminal and copy/paste this:

And in this file, use the same command as explained above (under a and b) for launching GIMP.

TIP: If you change Toolbox or the "Layers, Channels, Paths..." dialogs and they don't stick in GIMPBox anymore, close GIMP and run the following command to fix this:

Thanks to Pinguy for sending us the tip; info via PinguyOS forums (we've adapted the instructions for Unity / Appmenu; if you use the old GNOME2 Global Menu panel applet, see Pinguy's post for instructions on getting the menu to show in in GIMP/GIMPBox).

I tried this in june.
Didn't work then,doesn't work now.
Gimp windows open alright but then it quits w/o any error message.
Gerard.

Well it worked for me. Except I hated the 2 sec delay. As well as the custom dialogs I set, it doesn't remember them you haft to set it to show everytime.

My biggest pet peve on the whole GimpBox is hotkeys didn't work.

Everything else worked fine for me.

must be for linux only? i tried putting the .py file in plugins and in py folder but it's not showing up anywhere
win 7
gimp 2.6.11

No this is Linux only.
But it doesn't work.
Gerard.

ok thanks, i removed them so they don't mess with my other python scripts