We have a set of dashboards which have just 1 web part each. While updating one of these, I went into Web Part Maintenance and closed the only web part. According to several sources (like this youtube video), all I need to do is go into the ribbon to edit the page and re-add the closed web part.
Unfortunately, for unknown reasons (I didn't make them), that entire ribbon isn't visible on these pages. How do I re-enter editing mode so that I re-add my web part?
You can remove wrong webpart. Just add ?contetns=1 to the .aspx-page url. Some helpfull link are described there: http://blogs.msdn.com/b/how24/archive/2013/05/23/famous-sharepoint-urls-amp-locations.aspx