quick fix existing filter updates

frontend/app/components/wp-fast-table/wp-table-filters.ts

@@ -43,7 +43,15 @@ export class WorkPackageTableFilters extends WorkPackageTableBaseState<QueryFilt
   public current:QueryFilterInstanceResource[] = [];
 
   public comparerFunction():(current:QueryFilterInstanceResource[]) => any {
-    return (current:QueryFilterInstanceResource[]) => current.map((el:HalResource) => el.$plain());
+    // TODO: this should be
+    //
+    // return (current:QueryFilterInstanceResource[]) => current.map((el:HalResource) => el.$plain());
+    //
+    // instead. But for some reasons deeply burried probably within the
+    // HalResource, filters received from the server will not set the
+    // HalResource's source correctly when updating the values, operators ...
+    // Filters created in the frontend itself behave as expected.
+    return (current:QueryFilterInstanceResource[]) => current.map((el:HalResource) => _.cloneDeep(el));
   }
 
   constructor(filters:QueryFilterInstanceResource[], schema:QuerySchemaResourceInterface) {