Hello. Before the update to Firefox 42.01 on the Nightly channel, I used a custom start page that would open whenever I opened a new tab or browser window. I did this by creating a custom .html file, going into the config files of Firefox and telling it to open this file whenever I opened a new tab. This worked great before, but since this update and the implementation of the new tab system, this doesn't work anymore. I checked my config files and it still links to my custom .html file, but Firefox won't open this. Is there any way to use my custom start page instead of the built-in one from Mozilla? Thanks in advance for your help.