10.2. Allowing the end-user to build different queries in multiple windows
There's a QueryBuilderControl.MultipleQueriesPerSession property that instructs to allow this being set to true.
Note that in this case the queries built by the end-user will not be saved to a session automatically.
This property must be set in HTML code, in the attributes of the control; setting it programmatically is useless:
<AQB:QueryBuilderControl ID="QueryBuilderControl1" runat="server" OnInit="QueryBuilderControl1_Init" MultipleQueriesPerSession="True" />