When you are working in the Source view, you can use F3 to navigate through the file by placing your cursor in the appropriate item and pressing F3 to jump to the item it refers to.
You can jump to any of the following items:
You must place your cursor exactly in the location of the reference (for example between the double quotes for type = " " or base = " ").
For example, if you place your cursor anywhere in the following text and press F3:
<element name="shipTo" type="po:USAddress"></element>
the cursor will automatically jump to the location in the file where the type USAddress is defined.
Or, if you place your cursor anywhere in the following text and click F3:
<element ref="po:ContactElement"></element>
the cursor will automatically jump to the location in the file where the global element ContactElement is defined.
This works across files. For example, if the type you have selected is defined in another XML schema and you click F3, you will automatically be taken to that file.