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Note that child objects are denoted with the 
icon while properties use the 
icon.
As stated above, if you select an object (ie. $Build.$), all the object's properties and sub-objects will be shown in the drop down.
Accessing Variables through Expressions
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Note that namespaces are denoted with the 
icon while variables use the icon.
If you select a namespace then you will only see variables in that namespace.
Drop Down Usage and Auto Complete Shortcut keys
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