The file '<file>' is already open in an editor
Error MessageThe file '<file>' is already open in an editor. Please close the file and try again.
This error message can occur when you have the default .resx or .settings file already open in the stand-alone Resource Editor or Settings page, and then you open the Project Designer and go to the Resources page or Settings page. The right pane of the Project Designer will emit this message because the development environment cannot open the same file in the same type of editor in two different places.
To correct this error
Go to the stand-alone Resource Editor or Settings page and close it, and then go back to the Project Designer and re-select the tab. You will then see the page displayed properly.