diff --git a/src/bufferlist.h b/src/bufferlist.h
index c948d1b1ce..f43725a76e 100644
--- a/src/bufferlist.h
+++ b/src/bufferlist.h
@@ -99,6 +99,7 @@ private:
 	void emergencyWrite(Buffer * buf);
 };
 
+/// Implementation is in lyx_main.C
 extern BufferList & theBufferList();
 
 #endif // BUFFERLIST_H
diff --git a/src/frontends/Clipboard.h b/src/frontends/Clipboard.h
index d75f3cf4a4..c6182bc7c0 100644
--- a/src/frontends/Clipboard.h
+++ b/src/frontends/Clipboard.h
@@ -44,6 +44,7 @@ public:
 } // namespace frontend
 } // namespace lyx
 
+/// Implementation is in Application.C
 extern lyx::frontend::Clipboard & theClipboard();
 
 #endif // BASE_CLIPBOARD_H
diff --git a/src/frontends/FontLoader.h b/src/frontends/FontLoader.h
index 9000353cf3..dc4b7458d6 100644
--- a/src/frontends/FontLoader.h
+++ b/src/frontends/FontLoader.h
@@ -41,6 +41,7 @@ public:
 } // namespace frontend
 } // namespace lyx
 
+/// Implementation is in Application.C
 extern lyx::frontend::FontLoader & theFontLoader();
 
 #endif // QFONT_LOADER_H
diff --git a/src/frontends/FontMetrics.h b/src/frontends/FontMetrics.h
index 16dbf00f70..41b526caf2 100644
--- a/src/frontends/FontMetrics.h
+++ b/src/frontends/FontMetrics.h
@@ -116,6 +116,7 @@ public:
 
 class LyXFont;
 
+/// Implementation is in Application.C
 extern lyx::frontend::FontMetrics const & theFontMetrics(LyXFont const & f);
 
 #endif // FONT_METRICS_H
diff --git a/src/frontends/Selection.h b/src/frontends/Selection.h
index c281d72cc5..6a46417206 100644
--- a/src/frontends/Selection.h
+++ b/src/frontends/Selection.h
@@ -48,6 +48,7 @@ public:
 } // namespace frontend
 } // namespace lyx
 
+/// Implementation is in Application.C
 extern lyx::frontend::Selection & theSelection();
 
 #endif // BASE_SELECTION_H
diff --git a/src/lyxfunc.h b/src/lyxfunc.h
index 399d0739d2..428709ce15 100644
--- a/src/lyxfunc.h
+++ b/src/lyxfunc.h
@@ -119,8 +119,10 @@ extern LyXFunc & theLyXFunc();
 
 namespace lyx {
 
+/// Implementation is in frontends/Application.C
 extern FuncStatus getStatus(FuncRequest const & action);
 
+/// Implementation is in frontends/Application.C
 extern void dispatch(FuncRequest const & action);
 }