The boxes are the same size. This is default behavior. There are two options that change it. Figure 13.2a resized. By default, horizontal slices grow or shrink horizontally to fit the space available to them.
Vertical slices grow or shrink vertically.
The widgets associated with them do not grow or shrink. If their slices become too small for them, they will be truncated. To make widgets grow with their slices, use -fill both . The middle slice in Figure 13.2b is packed the same way as in Figure 13.2a. The first slice is packed with -fill both .