Make schematic and project inherit from PROJECT::ELEM

Just to see if anything weird happens first.

eeschema/schematic.h

@@ -24,6 +24,7 @@
 #include <embedded_files.h>
 #include <sch_sheet_path.h>
 #include <schematic_settings.h>
+#include <project.h>
 
 
 class BUS_ALIAS;
@@ -64,7 +65,7 @@ public:
  * Right now, Eeschema can have only one schematic open at a time, but this could change.
  * Please keep this possibility in mind when adding to this object.
  */
-class SCHEMATIC : public EDA_ITEM, public EMBEDDED_FILES
+class SCHEMATIC : public EDA_ITEM, public EMBEDDED_FILES, public PROJECT::_ELEM
 {
 public:
     SCHEMATIC( PROJECT* aPrj );
@@ -354,6 +355,8 @@ public:
     void Show( int nestLevel, std::ostream& os ) const override {}
 #endif
 
+    PROJECT::ELEM ProjectElementType() override { return PROJECT::ELEM::SCHEMATIC; }
+
 private:
     friend class SCH_EDIT_FRAME;
 

include/project.h

@@ -78,6 +78,9 @@ public:
 
         DESIGN_BLOCK_LIB_TABLE,
 
+        SCHEMATIC,
+        BOARD,
+
         COUNT
     };
 

pcbnew/board.h

@@ -40,6 +40,7 @@
 #include <title_block.h>
 #include <tools/pcb_selection.h>
 #include <shared_mutex>
+#include <project.h>
 #include <list>
 
 class BOARD_DESIGN_SETTINGS;
@@ -291,7 +292,7 @@ enum class BOARD_USE
 /**
  * Information pertinent to a Pcbnew printed circuit board.
  */
-class BOARD : public BOARD_ITEM_CONTAINER, public EMBEDDED_FILES
+class BOARD : public BOARD_ITEM_CONTAINER, public EMBEDDED_FILES, public PROJECT::_ELEM
 {
 public:
     static inline bool ClassOf( const EDA_ITEM* aItem )
@@ -1301,6 +1302,8 @@ public:
      */
     COMPONENT_CLASS_MANAGER& GetComponentClassManager() { return m_componentClassManager; }
 
+    PROJECT::ELEM ProjectElementType() override { return PROJECT::ELEM::BOARD; }
+
     // --------- Item order comparators ---------
 
     struct cmp_items