Currently, the Ctrl-Shift-N behavior is to NOT propose files
that would match the criteria but have an unknown (non-associated)
This can be terribly confusing (and worse, misleading) especially
for new users.
Wouldn't it make sense to show those files in the Ctrl-Shift-N popup
and if selected, ask for a possible type association? This would be
more consistent with the project-view tree which shows ALL files.
By the same token, Search In Path ignores files with an unknown
extension. This recently led to a bug on our team where a wide
renaming issue was marked as 'resolved' even though later on we
discovered that the installer configuration files (plain-text) had been
missed by the fix. It would have been nice to have the option to
search ALL files.