...

src/calibre/gui2/widgets2.py

@@ -134,6 +134,17 @@ class RightClickButton(QToolButton):
 
 class Dialog(QDialog):
 
+    '''
+    An improved version of Qt's QDialog class. This automatically remembers the
+    last used size, automatically connects the signals for QDialogButtonBox,
+    automatically sets the window title and if the dialog has an object names
+    splitter, automatically saves the splitter state.
+
+    In order to use it, simply subclass an implement setup_ui(). You can also
+    implement sizeHint() to give the dialog a different default size when shown
+    for the first time.
+    '''
+
     def __init__(self, title, name, parent=None, prefs=gprefs):
         QDialog.__init__(self, parent)
         self.prefs_for_persistence = prefs