I am using QGis (latest version, OS X) and whan I create a map on map composer everything works fine. I export the map to pdf file and also goes fine. But when I save and close it and then close the main project and then open it again and then open the map composer that I saved, that map does not show anymore. However, I can still export the map but when it comes to editing I can't because everything is white. The commamd history appears empty. When opened on another computer (PC version) with a different version of QGis works fine. Here is the printscreen of my issue.