However, the Tk text and canvas are so powerful, and Tk so extensible, that developers have lived without new features by relying on free extensions. Text embeds both a compact visual editor and an HTMLv2 display engine, and defines sophisticated tag programming, making visual effects easy. Browsers depend on cursor movement and selection by clicking. Tk's text and related widgets such as button and label suffice for most form-based GUI programming. Applications in geographic information systems, electronic design automation, and complex visualization require a second level of graphics to display and manage arbitrary drawings such as maps, engineering diagrams, and images.
Many successful programmers work only on form-based office automation tasks.
However, Tk's canvas can help those with more general needs. Tk is the established basis for successful commercial GUI applications, many of which have stringent requirements for scale and performance. Geometry Tk's fans also laud the toolkit for its geometry management. Geometry is the positioning of widgets on the visual screen. Windows's Visual Basic is reputedly easy for beginners because of its IDE's facility for dragging and dropping widgets into a form.