Not overwritten pages after migration will unhide Technical Content spaces

After testing several migrations from older versions (2.7.2 in my case) I have seen that for example leftover pages like the existing color themes are not marked as hidden, thus, after migrating to 4.1.1 spaces that contain old/leftover documents will make the spaces they are in visible.

pages:

• BlueSky, Bordo, InnerDark, Natural, Nightfall, Peach for the ColorThemes Space
• ClassEditorWelcome, GlobalRightsEditorWelcome, Tags, WebPreferences for Panels space (there might be others too) will not be deleted and they won't be marked as hidden.

So these leftover pages from previous versions will unhide a space and make it visible in the Spaces macro, because they contain unhidden documents.

This does not offer consistency in our upgrades, and might confuse users.

Also, please note that creating a new page in these spaces does not make the page hidden by default, so the space could show up because it contains a not hidden page.

This issue was raised on the lists, but since no one responded, I am reporting it in JIRA. This might not be a bug, but more a unexpected/unwanted behavior.

Issue was first raised in: http://markmail.org/message/dsafamn5lyzm2vkz