Loading default custom shapes in custom shape palette
Custom shapes are recreated vector shapes that can be reused time and again. For using a custom shape select custom shape tool. From options bar at top, click on small arrow next to "shape". This'll open a flyout with the default or stored custom shapes.
To view custom shapes according to a particular category click the small arrow on top right of the flyout. Select the category from the drop down list.
It will ask you if you want to replace the entire content of flyout with the new category or you want to append it.
If you are not looking for a particular custom shape and you just want to browse all available custom shapes click on "All" from the drop down list.
It will list out all available custom shapes from where you can choose what you are looking for.