Can I choose to not sort directories before files on file open dialogs?

I have a solution for GTK applications, and a solution for dolphin. I've never figured out how to fix this for non-GTK applications (e.g., LibreOffice).

For GTK:

1. Fire up dconf-editor.
2. Navigate to org/gtk/settings/file-chooser.
3. De-select the box next to sort-directories-first.
4. Close the dialog.

For dolphin:

1. Navigate to Control / Sort by >.
2. De-select "Folders first" at the bottom of the menu.

Hope this helps.

EDIT: I see someone else asked / addressed this problem here. I mention it because that thread has an easy command-line answer for the GTK+ part:

gsettings set org.gtk.Settings.FileChooser sort-directories-first true

In Thunar just set the option in the (edit>)preferences under view.