With latest updates this bug is now in standard client on Ubuntu 16.04.
Also getting this on Arch
Please release a fix for this soon. This is one of the most annoying bugs ever.
Confirming the same behavior on a fresh install of Ubuntu 16.04 x64 using the non-beta client. The xdg-open binary is in /usr/bin/ as expected, but Steam can't find it for whatever reason.
This is fixed in the latest Steam beta update (1468520696):
Linux
Fixed handling of clickable URLs in chat text for the desktop Steam client
I will close this issue.
Nothing extracted yet.
When I click on any external Link in the Steam client (Forums, Chat etc.) nothing happens. I get this error on the console when I click on a link:
However, xdg-utils are installed and xdg-open is present: