Some Tk classes are missing from Figure 2.13, “The Tk Palette”. These items are hidden inside the palette. Use the customize command, from the »context menu«, to make them accessible.

Scale

I only used the scale control once inside of a prototype. This control has massive design flaws –not-only in Tk. Tk itself has a use-case for scale, inside the X Window System colour dialog, but avoids it!

Groupbox

In Tk called »labelframe«; leads to baroque designs. According to the usability literature: Never use such controls.

A in-depth problem description can be found in: "Object Oriented User Interface Design" by Theo Mandel. Also consult the AQUA® HCI Guidelines.

Panedwindow

A container window with a built-in geometry manager. Allows interactive resize operations.

Better use »rtlxsizer« and »rtlysizer« instead. rtlxsizer and rtlysizer interact with the grid geometry manager, used inside their parent window. These windows can be added after completing the design.

Scrollbar

Use the »rtl_gridwin« instead.

rtl_gridwin, provides scrollbars and manages them together with the client window.