Gtk-WARNING while using gksu

Solution 1:

Those are more or less harmless.

The first one is about a missing GTK engine.

For your specific error:
```
sudo apt-get install gtk2-engines-pixbuf
```
To find the package in error:
```
sudo apt-get install apt-file
```
Search for the module name that is given in your error i.e. prefix with lib and suffix with .so - so in your example pixmap, you need to search for libpixmap.so
```
apt-file find libpixmap.so
```
This will give the package to install e.g.
```
gtk2-engines-pixbuf: /usr/lib/i386-linux-gnu/gtk-2.0/2.10.0/engines/libpixmap.so
libgtk2.0-0-dbg: /usr/lib/debug/usr/lib/i386-linux-gnu/gtk-2.0/2.10.0/engines/libpixmap.so
```
The second one happens because the root user (/root directory) doesn't have a .local directory. You can create it by running:
```
sudo mkdir -p /root/.local/share
```