Tk provides many widgets commonly needed to develop desktop applications, such as button, menu, canvas, text, frame, label, etc.
Tk was written originally for Unix/X11, and proved extremely popular with programmers in the 1990s by virtue of its being easier to learn and use than Motif and other X11 toolkits of the time.
The embedded Tk provides a simple mechanism for creating graphical user interfaces.
[13] Widgets that became commonly used in applications (e.g. trees, combo boxes, tabbed notebooks) were not available in the Tk core, but only via multiple, often competing add-ons.
[14] Tk 8.5, released in late 2007, corrected some of these problems by adding missing widgets to the core, introducing a new theming engine and modernizing the look and feel on Unix.
[8] However, because some code changes were required to incorporate these advancements, many existing applications retain the older Motif-inspired feel that Tk had become known for.