Custom EditForm.aspx page error “The page you have selected does not contain a reference to the correct SharePoint list”

If you are trying to create a custom property editor screen for a document library (to replace the default EditForm.aspx page), you might follow Jan Tielens instructions on how to do it for a normal list.  That works fine for a normal list, but when you try to do the same with a document library, when you click the Apply button in the Supporting Files tab in SharePoint Designer you’ll get an error:

The page you have selected does not contain a reference to the correct SharePoint list. Please select another page

To avoid this you need to make sure that the original ListForm web part is still there in the markup on the page, but you make it invisible and add a custom list form web part above it.  But you also need to remember that how to create your custom edit page is important as well.  You might think the easy way is to do this:

• Open the site in SharePoint Designer
• Select the EditForm.aspx in the Forms folder of the document library
• Right click – Copy
• Select the Forms folder
• Right click – Paste

That will create a copy of the EditForm.aspx file that you can rename and work with but you keep getting the error above when you try to apply it to the document library.  So instead create the custom editor page  like this:

• Open in SharePoint Designer
• Open the EditForm.aspx in the Forms folder of the document library
• Save it with a different filename

Now start editing your new page.  Remember not to delete the existing ListForm web part, just make it invisible.