Instructions on how to get Gtk3 indicators in a Gtk2 Xfce-Panel

Installation

Step 1: Install dependencies

sudo apt-get build-dep xfce4-panel libxfce4ui xfce4-indicator-plugin
sudo apt-get install git xfce4-dev-tools gtk-doc-tools libindicator3-dev libido3-0.1-dev

Step 2: xfce4-panel

git clone git://git.xfce.org/xfce/xfce4-panel
cd xfce4-panel
git checkout andrzejr/wrapper3
./autogen.sh --enable-gtk3
# (above you can add --prefix=/usr if you're not afraid of reinstalling your xfce4-panel with "sudo apt-get install xfce4-panel --reinstall")
make
sudo make install
sudo ldconfig # (to update libraries)
cd ..

Step 3: libxfce4ui

git clone git://git.xfce.org/xfce/libxfce4ui
cd libxfce4ui
./autogen.sh --enable-gtk3
make
sudo make install
sudo ldconfig
cd ..

Step 4: xfce4-indicator-panel

git clone git://git.xfce.org/panel-plugins/xfce4-indicator-plugin
cd xfce4-indicator-plugin
./autogen.sh
# (if you used --prefix=/usr before, use it again here)
make
sudo make install
cd ..

Gtk3 Indicators

sudo apt-get install indicator-power indicator-bluetooth indicator-datetime indicator-keyboard indicator-printers indicator-sound indicator-sync indicator-messages
sudo apt-get purge indicator-sound-gtk2 indicator-application-gtk2

Usage

Run xfce4-panel --restart and your panel might look half-empty. Be sure to either backup your config (~/.config/xfce4/..) or be ready to recreate your panel by hand. The first time you run it you might get crashes because gtk2 indicator backends are still running. You can ignore this.

Known Issues

indicator-datetime config panel

You can't access it unless you are running Unity. This affects gnome-classic too. #1074314

Various indicators have no menu

This isn't specific to any DE. Test case affects Unity too. #1203888 (fixed in saucy and trusty.)

Datetime/Session indicators sometimes don't load at startup

Affects other sessions. #1239710 (fix is in proposed.)