*Draw the background on the desktop window, using the same code as on navigation windows to bypass the no-root-window issue.
*Works from caja's "Change Desktop Background" menu item, from caja-extensions "set as wallpaper" and with changing the background in dconf-editor.
*All background options available in x11 supported in wayland, UI is new for wayland
*Apply changes immediately, keep the dialog open until closed by user
*Let users see changes in realtime while keeping the dialog open
*Preview both colors and pictures
*Add ability to apply changes from either combobox including using any image saved from when dialog was opened
*Add tooltips to the buttons, filepicker, and comboboxes