Define google-chrome as default Web browser in Thunderbird

To define google-chrome as default Web browser in Thunderbird, there is two steps to follow.
Step 1 (may be enough):
 - open advanced configuration editor (Edit->Preferences->Advanced->Configuration  Editor)
 - define following properties with /usr/bin/google-chrome
network.protocol-handler.app.http
network.protocol-handler.app.https

Step 2:
Usually there is embedded configuration in mimeTypes.rdf file of your Thunderbird profile. In this case, step 1 is not enough.

To define default Web browser:

 - open advanced configuration editor (Edit->Preferences->Advanced->Configuration  Editor)

 - define following properties with true

network.protocol-handler.warn-external.http

network.protocol-handler.warn-external.https

 - open a http link -> the first time there will be a popup, define /usr/bin/google-chrome as your default Web browser, and activate the check box for memorizing this configuration

 - open a https link -> and do the same

You will see that mimeTypes.rdf file will have been edited.

This time, google-chrome will really be the default Web browser in Thunderbird.