Promote "checkout" from the "advanced" sub-menu to the primary context (right click) menu
Editing an excel file on sharepoint while in a browser session requires the document to be checked out first. If the document is not checked out first, user gets an instruction saying, “To edit this workbook, check out the workbook in the Folder to the server (not to your local drafts folder) and then try to edit it in Excel Online again.” It is very easy to forget to check out the document in the first place because the checkout command is buried under ‘Advanced’ in the context menu. Why not move it right up to the top next to “Open in Excel Online”. It would be on less click and the user will quickly learn better habits.