only falkon and firefox can be set as default browser

[Roberalz]

STEPS TO REPRODUCE
 1. Install chromium-browser
 2. Load lxqt-config-session ("Session Settings" in menu)
 3. Click on "Default Applications"

EXPECTED RESULTS
 * Chromium should be on the list of "Web Browser" options
 * Clicking "Search" and entering chromium-browser should add it if not

ACTUAL RESULTS
 * Chromium is not on the list of "Web Browser" options
 * Clicking "Search" and entering chromium-browser seems to be accepted, but upon reloading lxqt-config-session, it fails.

AFFECTS
 * lxqt-config 0.13.0-0ubuntu4
 * Other browsers:
   1. dillo
   2. hv3
   3. qutebrowser
   4. surf

WORKAROUND (https://github.com/lxqt/lxqt/issues/1560)
 1. Enter the executable name in the list field.
 2. A dialog will pop up saying that changes will take affect at next login.
 3. Log out and back in again.
 4. Now e.g. `xdg-open http://lubuntu.me` will work.

NOTES
Seems Chromium is particularly problematic in this regard. This bug discusses it and offers some solutions:
https://github.com/lxqt/lxqt/issues/1513

There's a larger problem here, i.e. that using the BROWSER environment variable to set the default browser is problematic. It looks like upstream will fix it. Meanwhile, I suggest removing the definition of BROWSER from {/etc/xdg/xdg-Lubuntu/lxqt,$HOME/.config/lxt}/session.conf and change the value of the default browser with `xdg-settings set default-web-browser DESKTOP` where DESKTOP is the name of the desktop file associated with the browser (most likely in /usr/share/applications).

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

I'm not sure of the mechanism Chromium uses, but you should set the default applications in LXSession Settings.

[Roberalz (roberalz)]

LXSession Settings chromium in the list, they list has falkon and firefox, you have to add it manually

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

It seems even adding it manually doesn't work?!

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

There's a workaround now, but it should be noted that only changes the value of $BROWSER. It does not change the value of `x-www-browser` (see the Alternatives Configurator) nor does it set the "File Associations" correctly.

It should also be noted that even when after making changes to all three of those, it still complains it's not the default browser. Even after clicking its own button to set it as default. That's probably a separate bug to file against Chromium, and not one likely specific to Lubuntu.

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

As of today's Lubuntu 19.04 with lxqt-session 0.14.1, I can confirm this is now fixed in that it is possible to set other values for the default browser.

That said, not all browsers show up in the list when installed. falkon, chromium-browser, and dillo do not show up. They can be added with the search option, though.

The problem with this, though, is that it's setting the BROWSER environment variable and it doesn't change the file associations. Furthermore, the BROWSER variable can create problems changing default browsers (see https://launchpad.net/bugs/1823917).

Using `xdg-settings set default-www-browser chromium-browser.desktop` (or whatever the desktop filename is) does seem to change file associations, url scheme handlers, etc. This is the most robust way to change default browsers, especially for browsers like falkon and dillo which don't have an in-build way to make them default. It's clear given the bug above that's what chromium-browser uses.

[Roberalz (roberalz)]

Ok, Thanks!!!