I have set Chrome as default Internet browser. But Thunderbird still chooses to open some links in Chrome and some in Firefox.
Can I force Thunderbird to open all links in Chrome only?
Follow the step to set Default Browser for all Thunderbird mail links
The method described by Vipul Bhatt stop working for me, at least in Thunderbird version 52.5.0 (Ubuntu 16.04). I found a way going into the "Attachments" tab in "Peferences" menu and searching for "http" and "https", and then changing values to the browser I want or to "Allways ask". Problem solved.