Select the object you want to colour.
In the colour bar, click on a colour to change the colour of the selected item.
Right-click on a colour bar to display a shortcut menu, from which you can select the item you want to change the colour of.
Note:
If you have selected a graduated fill style A fill style that graduates from one colour to another., you can change the from and to colour using the colour bar:
To change the from colour, click or Ctrl-click on the colour in the colour bar.
To change the to colour, Shift-click on the colour in the colour bar or right-click on the colour and select Frame Grad Fill from the shortcut menu that appears.