get masks from gDoc

GUI/View/Canvas/MaskEditorCanvas.cpp

@@ -15,6 +15,7 @@
 #include "GUI/View/Canvas/MaskEditorCanvas.h"
 #include "Device/Data/Datafield.h"
 #include "GUI/Model/Data/Data2DItem.h"
+#include "GUI/Model/Device/InstrumentsSet.h"
 #include "GUI/Model/Mask/MasksSet.h"
 #include "GUI/Model/Project/ProjectDocument.h"
 #include "GUI/View/Canvas/SavePlotAssistant.h"
@@ -117,9 +118,10 @@ void MaskEditorCanvas::onPresentationChange(bool pixelized)
         m_data_item->setInterpolated(m_backup_interpolated);
     }
 
-    if (auto* container = m_data_item->masksSet())
-        for (MaskItem* t : *container)
-            t->setIsVisible(!pixelized && t->wasVisible());
+    if (const InstrumentItem* ii = gDoc->instruments()->currentItem())
+	if (const MasksSet* s = ii->masks())
+	    for (MaskItem* t : *s)
+		t->setIsVisible(!pixelized && t->wasVisible());
 }
 
 //! Saves plot into project directory.