possibility to hide filters in history and workspace view (bug#45428) * history_dock_widget.cc(construct): use settings file for show/hide the filter; (~history_dock_widget): save current filter state to settings file; (ctxMenu): add menu entry for showing/hiding the filter; (handle_contextmenu_filter): slot for the new menu entry * history-dock-widget.h: new slot for new menu entry, new class variables for filter and show/hide-state * workspace-view.cc(workspace_view): use settings file for show/hide the filter; (~workspace_view): save current filter state to settings file; (contextmenu_requested): add menu entry for showing/hiding the filter; (handle_contextmenu_filter): slot for the new menu entry * workspace-view.h: new slot for new menu entry, new class variables for filter and show/hide-state

--- a/libgui/src/workspace-view.h	Wed Oct 07 07:41:44 2015 -0700
+++ b/libgui/src/workspace-view.h	Wed Oct 07 21:01:25 2015 +0200
@@ -70,6 +70,7 @@
   void handle_contextmenu_disp (void);
   void handle_contextmenu_plot (void);
   void handle_contextmenu_stem (void);
+  void handle_contextmenu_filter (void);
 
   void handle_model_changed (void);
 
@@ -92,6 +93,9 @@
   QSortFilterProxyModel _filter_model;
   QCheckBox *_filter_checkbox;
   QComboBox *_filter;
+  QWidget *_filter_widget;
+  bool _filter_shown;
+
   enum { MaxFilterHistory = 10 };
 };