I just posted version 4.3.1 of Default Folder X. It’s got fixes and improvements for users of Snow Leopard, Gmail, Final Cut Pro, and QuickTime. It also makes Default Folder X’s contextual menus work in icon and column view in Open and Save dialogs (they were missing in Snow Leopard).
If you want the toolbar to be on the left side of the Open and Save dialog instead of the right, install version 4.3.1 and then Option-click on the “Settings” button in the preference pane and turn on “ToolbarOnLeft”.
There are also some UI fixes, including eliminating that annoying white box that would occasionally show up in the menubar where Default Folder X’s menu icon was supposed to be.
Thanks for everyone that reported problems and tested fixes for them. If you have any issues or ideas, just email email@example.com.