Windows 10 has been available for developers to test their apps on for over 9 months and well publicized. It looks like VirtualBox didn't bother to take advant

Windows 10 has been available for developers to test their apps on for over 9 months and well publicized. It looks like VirtualBox didn't bother to take advantage of that window. It's likely not because it's free and open source (I've ensured my FOSS projects work on Windows 10 since the first public test version), it's likely because it's Oracle. Note that the first bug you linked is 4 months old but was ignored for months and the first comment posted to it just 10 days ago.