If you are trying to get an "Open" button on learn.co to launch their atom-based IDE and nothing is happening, you are probably missing a protocol handler. This is how I fixed the problem.
(Note this has only been tested on Ubuntu Linux 16.04 with KDE 5. It may not be valid for other configurations.)
- create a file in
$(HOME)/.local/share/applications
calledlearn-ide.desktop
. It should have atleast the following contents:
[Desktop Entry]
Type=Application