I am maintaining a Visual Studio Extension that uses the MPF Package class and is built in VS2012 to target VS2012-VS2015. This project creates multiple custom IPropertyPage-based property pages. On Visual Studio 2012, it works just fine, but on VS2015 I am running into an issue where when I open the Project->Properties window, close the window, and open it again, some of the property pages show the error: "The DocumentSite on a WindowFrame may only be set once".
Does anyone know what this error means and what causes this? "DocumentSite" and "WindowFrame" don't really come up with anything. I am not setting this site value anywhere. Should I be setting or releasing something in the IPropertyPage.SetPageSite function? I can't find anything related to this error online.
Thanks for any help,