Its kind of confusing that when you navigate to a folder with files in it, that it doesn't actually show the files, and that the button still says "Open...". Perhaps it should say "Import..." to signify that you cannot actually "Open" anything in that folder.
I agree that it would be better to label the button in the file chooser dialog "Import", since the menuitem opening the dialog is also called "Import file...". Please file an upstream bug for this.