GtkFileChooser: set_extra_widget? Why not add_action?

[Gregory Merchan <merchan phys lsu edu>]

Are there any extra widgets that could be reasonably added to GtkFileChooser
which could not be handled by adding GtkActions? Toggles and radio groups
would be supported directly. Any app needing something more complex could
provide a second dialog for it.

The benefit would be that a UI implementation could control the UI of the
extra actions. If placing a checkbox below or beside other widgets would
be appropriate for a particular UI implementation, it could do that. If
instead providing a check item on a popup menu would be more appropriate,
it would be able to do that.


Cheers,
Greg