The problem that has been found is that when you apply a multiselect serverside filter and you save the state of datatable then refreshing the broswer the filter is not send it in the request.
As an example the snippet: http://webix.com/snippet/daa2c585
Apply the multiselect filter and then refresh the broswer
The filter is not applied
BUT in simple serverSelectFIlter looks that works
http://webix.com/snippet/f2159d62