If you do that, you might be interested that e(fx)clipse by default searches for the fx-sources in a file named "javafx-src.zip" which is located next to your src.zip and attaches them to the Library-Path-Entry.
[...] > Is this the correct way to go about it? > > I also noticed that the jfxrt.jar from the latest JDK1.8 snapshot includes > com.sun.media.* packages which are not yet part of OpenJFX (at least I don“t > think so, as my modules/media directory is empty). Is there a reason for this? > Not opensourced yet IIRC Tom