Links in Thunderbird won't open the site in Waterfox

[stoneubi]

What happened?

I'm on

• Linux Mint 22.3 - Cinnamon 64-bit
• Thunderbird 140.11.0esr (64-Bit)
• Waterfox 6.6.14 (64-Bit)

Steps to reproduce:

• within an email in Thunderbird, click on any link to a website
• waterfox opens but
• the site won't open if at this time no other waterfox instance is running
• if at this time waterfox is already running, the site will open normally

I don't know, if this is only on my laptop but if not, it would be great, if this can be fixed.

On Firefox, this is not the case. The site opens normally.

Reproducible?

• I have checked that this issue cannot be reproduced on Mozilla Firefox.

Version

6.6.14 (64-Bit)

What platform are you seeing the problem on?

Linux

[gregzme17]

I have the same issue. Here are some observations I have made.

If Waterfox is not open, then clicking a link in Thunderbird opens a blank window that does not work.
If Waterfox is already open,then clicking a link in Thunderbird opens the link in a new tab correctly.

This does not appear to be an issue either way when using Proton Mail app instead of Thunderbird.

• Linux Mint 22.3 - Cinnamon 64-bit
• Thunderbird 140.11.0esr (64-Bit)
• Waterfox 6.6.14 (64-Bit)

Thunderbird is native deb / Mint package
Waterfox is Flatpak
Protonmail is a deb package

Waterfox is set as my default browser application and Thunderbird is set as my default mail application.