Query Tab in UI: Able to edit previous queries through previous button when a long running query is executing

Hi Eben

In ycsb dataset with 20 million docs:
http://172.23.100.193:8091/ui/index.html#/_p/ui/query/workbench

I m able to edit queries from previous button, that should not be allowed.
The query I issued:
select * from default where meta().id is not null;