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| How to add a custom action for BackInTime in Thunar ? |
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1./ Check

Check if you have the file /etc/xfce/xdg/Thunar/uca.xml
If you don't have it, fill it with that:
  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE actions [
    <!ELEMENT actions (action)+>
    <!ELEMENT action (icon|patterns|name|command|description|directories|audio-files|image-files|other-files|text-files|video-files)*>
    <!ELEMENT icon (#PCDATA)>
    <!ELEMENT command (#PCDATA)>
    <!ELEMENT patterns (#PCDATA)>
    <!ELEMENT name (#PCDATA)>
    <!ATTLIST name xml:lang CDATA #IMPLIED>
    <!ELEMENT description (#PCDATA)>
    <!ATTLIST description xml:lang CDATA #IMPLIED>
    <!ELEMENT directories EMPTY>
    <!ELEMENT audio-files EMPTY>
    <!ELEMENT image-files EMPTY>
    <!ELEMENT other-files EMPTY>
    <!ELEMENT text-files EMPTY>
    <!ELEMENT video-files EMPTY>
  ]>
  <actions>
  </actions>


2./ Fill

Add the following action before the </actions> line:
  <action>
    <icon>gtk-save</icon>
    <patterns>*</patterns>
    <name>Open with BackInTime</name>
    <name xml:lang="fr">Ouvrir avec BackInTime</name>
    <name xml:lang="de">Mit BackInTime öffnen</name>
    <name xml:lang="el">Άνοιγμα με το BackInTime</name>
    <command>backintime-gnome %f</command>
    <description>Go back to an old version</description>
    <description xml:lang="fr">Revenir à une ancienne version</description>
    <description xml:lang="de">Zu einer alten Version zurückkehren</description>
    <description xml:lang="el">Επιστροφή σε προηγούμενη έκδοση</description>
    <directories/>
  </action>


3./ Enjoy :)