I can't change the default web browser

what you’re trying to achieve

The default browser is Mozilla Firefox. I want to change it to Epiphany, because it starts faster.

what steps you take

I have changed the nominated default in System Settings...-->Details--> Default Applications to Epiphany. (I have also updated both /etc/hosts and /etc/hostname.) I have also followed all the steps in

https://help.ubuntu.com/community/WebBrowsers

which are

Setting Default Browser

In the command line, type sudo update-alternatives --config x-www-browser

A list of installed browsers will be displayed with a different number next to each browser. Type the number corresponding to the browser of your choice.

defbrowser.png

what happens

However, if I right-click on a document of type 'HTML document (text/html)', there is no 'Open with...' option, so I select 'Open', and the web page opens with Mozilla Firefox. After carrying out each of the above steps, I restarted my computer each time, and I have just finished starting it again before writing this.

what you think should happen instead

If I right-click on a document of type 'HTML document (text/html)', and select 'Open', the web page opens with Epiphany.