GTK L&F: Behaviour of new folder button in JFileChooser is unlike native mercury

Behaviour of new folder button in JFileChooser is unlike native mercury.
By clicking on new folder button on native it opens the input dialog box unlike java implementation.

Steps to Reproduce:
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1) Run SwingSet2 on Mercury with -Dswing.gtkthemefile=<Your .gtkrc File>. Change the Look And Feel to GTK.
2) Go to FileChooser Demo.
3) Click on button 'Show Plain JFileChooser' and now click on 'New Folder' button, It simply creates a folder on that path.
4) Now open Gedit.
5) Click Open and click 'New Folder' button, It will show input dialog box and on saying ok it create folder. It is different than java implementation of the same.