Switch to side-by-side view

--- a/src/qtgui/rclmain_w.h
+++ b/src/qtgui/rclmain_w.h
@@ -136,7 +136,6 @@
     void docSourceChanged(RefCntr<DocSequence>);
     void stemLangChanged(const QString& lang);
     void sortDataChanged(DocSeqSortSpec);
-    void filtDataChanged(DocSeqFiltSpec);
     void applyFiltSortData();
     void searchReset();