make mask and projection classes more similar

Doc/graph/projn-classes.gv

@@ -9,7 +9,7 @@ digraph maskClasses
     Plot2DWithProjectionFrame->ProjectionActions;
     Plot2DWithProjectionFrame->ProjectionToolbar;
     Plot2DWithProjectionFrame->ProjectionsEditorCanvas;
-    Plot2DWithProjectionFrame->ProjectionsWidget;
+    Plot2DWithProjectionFrame->ProjectedGraphsCanvas;
     Plot2DWithProjectionFrame->Scale2DEditor;
 
     ProjectionActions->MaskeditorListmodel;
@@ -24,8 +24,8 @@ digraph maskClasses
     ProjectionsEditorCanvas->LineItem;
     ProjectionsEditorCanvas->Data2DItem;
 
-    ProjectionsWidget->ProjectionsPlot;
-    ProjectionsWidget->QTabWidget;
+    ProjectedGraphsCanvas->ProjectionsPlot;
+    ProjectedGraphsCanvas->QTabWidget;
     QTabWidget[style=filled fillcolor=beige];
 
     MaskGraphicsView->QGraphicsView[arrowhead=onormal color=chocolate4];