diff --git a/src/Mod/Drawing/Gui/Makefile.am b/src/Mod/Drawing/Gui/Makefile.am
index d2f8fa481..3116b04b0 100644
--- a/src/Mod/Drawing/Gui/Makefile.am
+++ b/src/Mod/Drawing/Gui/Makefile.am
@@ -20,6 +20,8 @@ libDrawingGui_la_SOURCES=\
 		PreCompiled.h \
 		TaskDialog.cpp \
 		TaskDialog.h \
+		TaskOrthoViews.cpp \
+		TaskOrthoViews.h \
 		ViewProviderPage.cpp \
 		ViewProviderPage.h \
 		ViewProviderView.cpp \