It could be expected. It's probably worth having some kind of disabled
reason listed somewhere at some point. For the time being, I'll
enumerate a few ways that this could get automatically disabled:
1) You could be running firefox.exe with command line arguments. We have
a finite list of command line arguments which are approved - if we see
anything outside that list we disable the skeleton UI. This covers, for
example, launching the profile manager, which is of course a window that
looks nothing like the typical main browser window. The list of approved
command line arguments is defined in code here:
2) You could be running with a theme other than the built-in dark,
light, and default themes. I suspect this is not true because you said
you're on a fresh profile. There are also a handful of other prefs which
will disable the skeleton UI if they're not the value we expect, but
again since you're on a fresh profile those should all be fine.
3) You could be running with any of these environment variables:
4) You could already be running an instance of firefox with the same path.
5) You could have configured firefox to always open the profile manager.
If it's outside those, then I think it's worth filing a bug or following
up with me outside of the list?
> Also, regarding the registry values, I only see one for the theme with a key referring to the path of the Nightly executable. How will you handle different profiles?
I hinted at this above in this message, but effectively we only allow
the skeleton UI if we are running the default profile. So if you have
firefox set up to always start the profile manager, or you specify a
profile via the command line or an environment variable, then we simply
bail out and don't show anything.
> Besides those issues, I'm really happy to see this coming. It improves perceived start up speed a lot, especially on less powerful machines.