While Joplin already have a multi-window support for Android Nougat and above, please add support to Samsung’s legacy multiwindow SDK to extend this feature to older phones, e.g. Samsung Galaxy Note 4.
OK so the documentation seems to have been removed.
Here’s an archive version of the documentation (hint: add properties to AndroidManifest.xml)
http://web.archive.org/web/20130327042239/http://developer.samsung.com/s-pen-sdk/technical-docs-09