Grafana 4.6.2 - Elasticsearch Datasource 5.x. Since update from 2.x to 5.x we cannot Remove the Filters Menue from the Dashboard. Normally we move the mouse over “Filters” - a Menue where visible i can remove all filter. But since we update the datasouce from 2 to 5 the Filter is always visible. We can only remove the filter if we reload the dasboard or Change to a another Dashboard.
Have a look at this Remove a Filter.
If that not helps you, can you export your dashboard as json and paste it in here?