10. An apparatus comprising: at least one memory configured to store information defining a placeholder widget comprising a roughly drawn sketch, the placeholder widget having a text property; and at least one processor configured to: execute a widget editor configured to define the placeholder widget; execute a GUI editor configured to receive information defining a prototype graphical user interface (GUI) that comprises an instance of the placeholder widget, wherein the widget editor is separate from the GUI editor; present the prototype GUI to a user, an appearance of the instance of the placeholder widget based on the text property of the placeholder widget; in response to a user selection of the instance of the placeholder widget, present a list of second widgets to the user and receiving a user selection of one of the second widgets; and in response to the selection of the selected second widget, replace the instance of the placeholder widget with an instance of the selected second widget in the prototype GUI and transfer the text property of the placeholder widget to the instance of the selected second widget.
10. An apparatus comprising: at least one memory configured to store information defining a placeholder widget comprising a roughly drawn sketch, the placeholder widget having a text property; and at least one processor configured to: execute a widget editor configured to define the placeholder widget; execute a GUI editor configured to receive information defining a prototype graphical user interface (GUI) that comprises an instance of the placeholder widget, wherein the widget editor is separate from the GUI editor; present the prototype GUI to a user, an appearance of the instance of the placeholder widget based on the text property of the placeholder widget; in response to a user selection of the instance of the placeholder widget, present a list of second widgets to the user and receiving a user selection of one of the second widgets; and in response to the selection of the selected second widget, replace the instance of the placeholder widget with an instance of the selected second widget in the prototype GUI and transfer the text property of the placeholder widget to the instance of the selected second widget. 11. The apparatus of claim 10 , wherein the at least one processor is configured to replace the instance of the placeholder widget with the instance of the selected second widget by transforming the instance of the placeholder widget into the instance of the selected second widget.