The "data-behind" a guided decision table is all held on the client-side. This does not facilitate (a) large data-sets, (b) use of Drools itself to perform contraction of columns (as Drools cannot - or will not - be compiled by GWT for use client-side, and it'd be crazy to marshal the whole model to and from the server just to contract). Moving the whole data-set to the server and having the UI only retrieve what is needed to display would enable these requirements.