Comment 2 for bug 1397768

I agree the current behaviour is not ideal. You can right-click on the blank line exposed by an expanded empty folder but it behaves like the root folder of the view, not the expanded folder. i.e. if you create a new file it gets created in the root folder, not the expanded folder which is not intuitive. However, you can drop files onto the blank row to add them to the empty folder. The dummy row is created by the fm_list_model which is why the expander appears.

For comparison, Thunar and PCMan do not show any expanders at all while Nautilus shows a blank line labelled "(empty)" for which most of the context menu is insensitive but which can be dropped on. Its probably easiest to follow the Nautilus behaviour.