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The PlanMaker spreadsheet has a sidebar which occupies about 15% of the spreadsheet display. I would like to either reduce or eliminate the sidebar so more attention can be devoted to the spreadsheet. But I cannot find a button to do so. Can someone tell me how this can be done?

How do I copy a cell, containing a formula, from tab 2 of the spreadsheet to tab 1 of that same spreadsheet? But as that cell in tab 2 changes in value, the change is reflected automatically in tab 1.