Press a Fill Pattern Palette button to change the fill pattern of the current selection.
Windows offers eight standard fill patterns - solid, empty and six hatch patterns. These are represented by the first eight buttons. The last two buttons are reserved for bitmap fill patterns, described below.
The Fill Pattern Palette buttons
Bitmap Fill Patterns
Windows does allow pictures to use bitmap fill patterns. However, these aren't used very often because they don't print well. The last two Fill Pattern Palette buttons are reserved for bitmap fills. However, they are disabled unless your picture already uses bitmap fill patterns.
Monochrome bitmap fills are special because their color is determined by the current Text and Background color - not the current Fill color.