Comment 3 for bug 919303

Fixing this might involve at least the following tasks:

- Find all reasons for invalidated Buttons and a way to provide this reasons to the ui.
- Add something to the ui, which provides the reason to the user using translatable strings.

Regarding the later part: One could add a label on the top of the pane, edit the current descriptions of the buttons (like we do when the gvfs-backend is not available) [1], or provide the information as a tooltip [2].

@typo and everyone affected: Do you have any preferences regarding these solutions?

[1] See the code for this inside of http://bazaar.launchpad.net/~deja-dup-hackers/deja-dup/34/view/head:/deja-dup/widgets/ConfigLabelDescription.vala

[2] See https://developer.gnome.org/gtk3/unstable/GtkWidget.html#gtk-widget-set-tooltip-text