
In order to define a new property in a project...
Open the Project Navigator and click with the right mouse button in order to activate the context menu.
Choose Properties in the context menu.
In the following properties dialog you can select an object type below the Administrate custom properties item the left side and add additional custom properties to it in the Custom Properties tab on the right side. There you also see all the currently defined custom properties.

Via the button Add
you can define new properties for the selected object type.
