diff --git a/libs/pbd/MSVCpbd/pbd.vcproj b/libs/pbd/MSVCpbd/pbd.vcproj
index 92c4723d2a..ec08afc65e 100644
--- a/libs/pbd/MSVCpbd/pbd.vcproj
+++ b/libs/pbd/MSVCpbd/pbd.vcproj
@@ -652,6 +652,10 @@
 				RelativePath="..\pbd\configuration_variable.h"
 				>
 			</File>
+			<File
+				RelativePath="..\pbd\control_math.h"
+				>
+			</File>
 			<File
 				RelativePath="..\pbd\crossthread.h"
 				>