You can use the Class Explorer to locate definitions of methods

1. Open the Delphi Class Explorer window by choosing ViewDelphi Class Explorer.
2. In the Class Viewer pane, click a a class or interface that declares the required method.
3. In the Member List pane, click the method to select it.
4. Click the right mouse button. In the appeared context menu choose the Go to Definition item. The source file in which the selected method is defined (implemented) will be opened in the text editor, the viewport will be positioned on the implementation of the method, and the implementation will be highlighted.