Abstract: A visual development system having an interface which assists a user with input of source code expressions and statements during creation of a computer program is described. The interface includes an Integrated Development Environment (IDE) interface having a code editor with “Code Completion” and “Code Parameter” features for displaying context sensitive pop-up windows within a source code file. Code Completion is implemented at the user interface level by displaying a Code Completion dialog box after the user enters a record or class name followed by a period. For a class, the dialog lists the properties, methods and events appropriate to the class. For a record or structure, the dialog lists the data members of the record. To complete entry of the expression, the user need only select an item from the dialog list, whereupon the system automatically enters the selected item in the code. Code completion also operates during input of assignment statements.