Can I use the groups manager to modify channel group settings?

In some cases, if you remove a particular channel from all channel categories it belongs to (a channel category is a channel group:  Applications, Development, etc.) then you will no longer be able to find it in the channel admin screen and in the groups manager. Even an open search on all channels will not return this channel. This is true with a few of the default portal channels: some channels remain available in both, some can only be found with an open search in groups manager, and some of them disappeared entirely. The channel admin screen will not allow you to continue without selecting at least one category for the channel you are creating/modifying, and uPortal is not expecting the channel to not belong to any categories. For this reason you should not modify channel category membership within the groups manager if possible. The channel publication is not actually deleted from the database, but it would require direct database manipulation to re-add a category to a channel that had 'disappeared' from the groups manager and channel admin (due to not being in any category).