I want to set Thunderbird's calendar extension, Lightning, as the default calendar app. Is this possible?
Thunderbird can be set as default calendar application by opening the file:
In a text-editor such as GEdit and adding the line
text/calendar=thunderbird.desktop to the [Default Applications] section. You may or may not need to add that same line to the [Added Associations] section too.
*To find and open this file, press the button combo Ctrl+H in your home folder, and look for
.local, then find the file, right-click it and Open with..., or just double-click. After adding the line, press CTRL+Q, answer YES when asked to save.
See also this comment in the bug report.
Edit the MIMETYPE line in /usr/share/applications/thuderbird.desktop to read:
sudo update-desktop-database -q
Now in "Default Applications" you will find Thunderbird in the list of calendar applications.
Calendar Extension for Thunderbird
Install this plug-in by clicking this link: xul-ext-lightning
or open a terminal (e.g. gnome-terminal) and type:
sudo apt-get install xul-ext-lightning
That's all, folks!