In DemoMap application, we can go to menu\files\open and choose a Mapwindow4Project (Mwprj) to open.
However, it go down to a bug. The bug is in "(DotSpatial.Plugins.MapWindowProjectFileCompatibility.DynamicXMLNode" .)
The error is in attached image: 
the source code is: 73351
The mapwindow is: MapWindow GIS v4.8.6 - Final release - 64Bit (https://mapwindow4.codeplex.com/releases/view/76562)
However, it go down to a bug. The bug is in "(DotSpatial.Plugins.MapWindowProjectFileCompatibility.DynamicXMLNode" .)
The error is in attached image: 
the source code is: 73351
The mapwindow is: MapWindow GIS v4.8.6 - Final release - 64Bit (https://mapwindow4.codeplex.com/releases/view/76562)