Workflow component dialog: variablePropertyComponent

I am creating a custom dialog for a workflow component.

I am using the variablePropertyComponent which has a"type" property which I can set to "java.lang.Long" and the drop down will filter all Long process variables.

However, I would like to NOT filter any variables by type. 

I have tried these things:

Remove type property

Add * as the type.

All these break it.

Anybody know how to do this?  Is it possible?