1. Open Thunar 2. Make sure you switch the path mode to buttons instead of text field 3. Click twice on the root folder icon (leftmost icon) Actual result: the root folders' icons are shown twice each.
Created attachment 1797 Screenshot
Please perform these steps to reproduce: 1. Open Firefox or any application and go to File->Open File 2. In "Open File" dialog, click the 1st icon on top, in the left corner to get the text input field for "Location" 3. Click the "<" icon to get to the root folder's icon (2nd from the left side, on top) 3. Click again the root folder's icon, observing the listed folders. Actual result: the root folder's icons are shown twice each. Please view the attached screenshot. Thanks!
This dialog is part of Gtk+, you should take this bugreport to bugzilla.gnome.org. It is neither part of Thunar, nor Firefox. I have confirmed the behaviour but this is a Gtk+ bug, please take the issue there.