This suggestion is similar to my edit, it hides the sidebar via button and moves the grid over or centers the feed.
Sorry if an idea to this has already been posted/considered.
We currently have the sidebar automatically move to the top when the width of the menu changes. This fixes the wider menu issue for most people. In addition, the sidebar is not visible when viewing individual submissions.
At this time, because there hasn't been much demand for this, we are going to pass on this idea. I can see some benefits that can come of it, but this would require a large amount of redesign for a feature that may not be used by many users.
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