Previously only application default values were possible

This helps the Window Manager decide how to display the window

This is a more flexible approach

default_text is returned if the value of the setting is an empty string

If the input textview is not sensitive it can’t get the focus. In that case propagate_key_event() would send the event again to the conversation textview. This would mean a recursion.

Fixes #10259

This allows other widgets to handle the ESCAPE Key first and only
if not other widget handled the key press exits the dialog

This allows to bind the value of a specific setting to a widget method
like set_sensitive() or set_visible()

Fixes #10258