GTK L&F: Folder list of the JFileChooser is allowing multiple selection unlike native

Folder list of the JFileChooser is allowing multiple selection unlike native file dialog. Where as the file list does not allow multiple selection.

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) Tab to Folder List
4) Press CTRL+A. It will select all the items in the list.
5) Now Tab to file list and press ctrl+A, it will not select all the items.
6) Now Open Gedit.
7) Click Open.
8) Repeat the steps 3 to 5. Behaviour for the native will be opposite to its Java counterpart.