Tumbler: disabling PDF and ODF

1. Rename/delete tumbler's shared library related to PDF and ODF file:
$ sudo mv /usr/lib/i386-linux-gnu/tumbler-1/plugins/tumbler-poppler-thumbnailer.so /usr/lib/i386-linux-gnu/tumbler-1/plugins/tumbler-poppler-thumbnailer.so.bak

$ sudo mv /usr/lib/i386-linux-gnu/tumbler-1/plugins/tumbler-odf-thumbnailer.so /usr/lib/i386-linux-gnu/tumbler-1/plugins/tumbler-odf-thumbnailer.so.bak

Replace i386 to x86_64 if you have 64 bit OS.

2. Regenerate thumbnails:
$ rm ~/.thumbnails

Fix missing flag xfce4-xkb-plugin

When I use this plugin to change the keyboard layout to arabic. Text "ara" is appear instead of arabic flag.

I see arabic flag in /usr/share/xfce4/xkb/flags/ which has name sa.svg. To display flag in panel, simply copy or make link to ara.svg from that file.
$ cd /usr/share/xfce4/xkb/flags/
$ sudo ln -s sa.svg ara.svg