Select the topic(s) you want to color.
Click the Fill/Highlight
color button 
on the bottom formatting toolbar.
Fill color is useful for calling attention to specific topics. Color can be added to topics from the bottom formatting toolbar and from the Format menu. Fill color can be used as a map marker and you can assign meaning to colors in the Map Markers List.
If the topic has a shape it is filled with the color, otherwise the color shows as a highlight behind the topic text.
Fill colors are not displayed in Outline view.
Hint: You can also use fill color markers as criteria for selecting topics and filtering the map.
To change the fill color:
Select the topic(s) you want to color.
Click the Fill/Highlight
color button on the bottom formatting toolbar.
Select the color from the color picker. The Fill color markers list shows in the bottom of the picker. If you select a different color, it will be added to the Fill Colors group in the Map Markers pane, where you can add a meaning for it (i.e. Critical task).
Notes:
Once you assign a name to
the new fill color in the Map Markers
pane, it will appear in the map legend and it will remain in the list
of map markers regardless of whether it is used on the map. If needed
you can modify the marker name and even select a different color to be
used for this marker.
If you do not assign it a name, the marker will disappear from the list
if it is no longer used on the map.
Shortcut: You can add a marker to the selected topic(s) by clicking on it in the Map Markers Pane.
To change both the fill color and transparency:
Select the topic(s) you want to color.
Do one of the following:
Right-click the topic and choose Format Topic - Shape and Color.
Click Format - Topic - Shape and Color.
Select the Fill color and Transparency % (0% is solid).
