ignore all drops that will not create usefull filter

apps/opencs/view/world/tablesubview.cpp

@@ -110,13 +110,17 @@ void CSVWorld::TableSubView::createFilterRequest (std::vector< CSMWorld::Univers
 {
     std::vector<std::pair<std::string, std::vector<std::string> > > filterSource;
 
-    for (std::vector<CSMWorld::UniversalId>::iterator it = types.begin(); it != types.end(); ++it)
+    for (std::vector<CSMWorld::UniversalId>::iterator it(types.begin()); it != types.end(); ++it)
     {
         std::pair<std::string, std::vector<std::string> > pair(                         //splited long line
-        std::make_pair(it->getId(), mTable->getColumnsWithDisplay(CSMWorld::TableMimeData::convertEnums(it->getType()))));
+            std::make_pair(it->getId(), mTable->getColumnsWithDisplay(CSMWorld::TableMimeData::convertEnums(it->getType()))));
 
-        filterSource.push_back(pair);
+        if(!pair.second.empty())
+        {
+            filterSource.push_back(pair);
+        }
     }
+
     mFilterBox->createFilterRequest(filterSource, action);
 }