Update docs, sip

python/core/layout/qgslayoutitem.sip

@@ -22,6 +22,9 @@ class QgsLayoutItem : QgsLayoutObject, QGraphicsRectItem
   public:
 
     QgsLayoutItem( QgsLayout *layout );
+%Docstring
+ Constructor for QgsLayoutItem, with the specified parent ``layout``.
+%End
 
     virtual int type() const = 0;
 %Docstring

python/gui/qgisinterface.sip

@@ -1193,6 +1193,30 @@ Get timeout for timed messages: default of 5 seconds
 .. versionadded:: 3.0
 .. seealso:: composerWillBeClosed()
 .. seealso:: composerOpened()
+%End
+
+    void layoutDesignerOpened( QgsLayoutDesignerInterface *designer );
+%Docstring
+ This signal is emitted when a new layout ``designer`` has been opened.
+.. versionadded:: 3.0
+.. seealso:: layoutDesignerWillBeClosed()
+%End
+
+    void layoutDesignerWillBeClosed( QgsLayoutDesignerInterface *designer );
+%Docstring
+ This signal is emitted before a layout ``designer`` is going to be closed
+ and deleted.
+.. versionadded:: 3.0
+.. seealso:: layoutDesignerClosed()
+.. seealso:: layoutDesignerOpened()
+%End
+
+    void layoutDesignerClosed();
+%Docstring
+ This signal is emitted after a layout designer window is closed.
+.. versionadded:: 3.0
+.. seealso:: layoutDesignerWillBeClosed()
+.. seealso:: layoutDesignerOpened()
 %End
 
     void initializationCompleted();

src/core/layout/qgslayoutitem.h

@@ -36,6 +36,9 @@ class CORE_EXPORT QgsLayoutItem : public QgsLayoutObject, public QGraphicsRectIt
 
   public:
 
+    /**
+     * Constructor for QgsLayoutItem, with the specified parent \a layout.
+     */
     QgsLayoutItem( QgsLayout *layout );
 
     //! Return correct graphics item type.