Connexion internet de Icedove

Bonsoir,
Je viens de passer à Chromium pour mes connexions internet au lieu de Firefox-esr. (beaucoup plus rapide).
Firefox est toujours installé , mais j’ai configuré Chromium comme navigateur prioritaire.
Hors Icedove se connecte toujours sur Firefox. Comment indiquer à Icedove de se connecter via Chromium?

(Debian Jessie sous openbox : Bunsenlabs)
Merci pour votre aide

Bonsoir,
Désolé je crois avoir posté un peu vite .
J’ai trouvé cela dans un forum Ubuntu:

Open Thunderbird. In 24.6.0, the menu can be accessed on the right hand side of the top menu bar (next to the search bar and is represented by three horizontal lines).

Click Edit > then click Preferences >, a new window will open. You will need to select the Advanced tab, at the bottom of that tab Open the Config Editor.

Then, search for both network.protocol-handler.warn-external.http and network.protocol-handler.warn-external.https.

These two are most likely to have a current value of false. Change the value to true (do this by simply right clicking on them) and the next time you try to open a link from some e-mail it’ll ask you which browser to use. Chromium isn’t likely to be shown in the list of choices, so use the navigate button. You can find Chromium at /usr/bin/chromium-browser.

Je vais tester