Add a widget to the splitter and make it visible.

        The only differences between this- and the native
        ``QSplitter.addWidget()`` method are

        1. ``widget`` must have a ``QtmacsAdmin`` structure to ensure it is a
           ``QtmacsApplet`` or a ``QtmacsSplitter``, 
        2. ``widget`` is automatically made visible.

        Both actions are mostly for convenience because adding ``widget`` to
        a QtmacsSplitter is tantamount to displaying it.

        |Args|

        * ``widget`` (**QWidget**): the widget to add to the splitter.

        |Returns|

        * **None**

        |Raises|

        * **None**

def qteAddWidget(self, widget):
        """
        Add a widget to the splitter and make it visible.

        The only differences between this- and the native
        ``QSplitter.addWidget()`` method are

        1. ``widget`` must have a ``QtmacsAdmin`` structure to ensure it is a
           ``QtmacsApplet`` or a ``QtmacsSplitter``, 
        2. ``widget`` is automatically made visible.

        Both actions are mostly for convenience because adding ``widget`` to
        a QtmacsSplitter is tantamount to displaying it.

        |Args|

        * ``widget`` (**QWidget**): the widget to add to the splitter.

        |Returns|

        * **None**

        |Raises|

        * **None**
        """
        # Add ``widget`` to the splitter.
        self.addWidget(widget)

        # Show ``widget``. If it is a ``QtmacsSplitter`` instance then its
        # show() methods has no argument, whereas ``QtmacsApplet`` instances
        # have overloaded show() methods because they should not be called
        # unless you really know what you are doing (it will mess with Qtmacs
        # layout engine).
        if widget._qteAdmin.widgetSignature == '__QtmacsLayoutSplitter__':
            widget.show()
        else:
            widget.show(True)

        # Adjust the sizes of the widgets inside the splitter according to
        # the handle position.
        self.qteAdjustWidgetSizes()