Support for about: pages

If I set e.g. about:preferences as website to open, at startup nothing will open at all.

[Faerbit]

I can reproduce this, but have no idea what's happening.

[nOrphf]

Not a developer, but I have read several times regarding other extensions, that these special pages is off limits for extensions, so I think that is why "an error" occur. That it should result in nothing opening is weird, but if it is your first page? it might explain that the extension errors and can't open the rest.