Opening a channel from the Channels overview does not always open with project = Core

Instead it opens with the project that the user has worked on last during the session.

From the Channels overview, the channel should always open with project = Core.
This is how it has always been, therefore it is what the user expects. And: 

Because the Channels overview is about core channels only (the information about unpublished changes for the channel in that overview is also only about Core), it is THE place to start editing the channel's Core. (Whereas from the Projects overview you always open the channel for a project and you cannot open Core directly.)