Also you can use predefinied properties to create diagrams briskly.
From the upcoming dialog you can select: The scope of modifications Color Transparency Outline Text frame Rounding properties. You might edit the whole diagram or just the selected items by selecting "User Define" from "Style of item" drop down box. You can remove one item selecting the shape then click on "Remove shape button". It is possble to convert compatible diagrams between each others. In case of Hierarchy Charts you also have to select the relation type of newly created item. Just select the color and type of item then click on "Add shape" button. Using this toolbar you can easily insert item to the diagram and remove items from the diagram or edit the properties of the items.