diff --git a/direct/src/gui/DirectGuiGlobals.py b/direct/src/gui/DirectGuiGlobals.py
index 59fd474900..04905e6d7b 100644
--- a/direct/src/gui/DirectGuiGlobals.py
+++ b/direct/src/gui/DirectGuiGlobals.py
@@ -70,6 +70,8 @@ B3PRESS = PGButton.getPressPrefix() + MouseButton.three().getName() + '-'
 B1RELEASE = PGButton.getReleasePrefix() + MouseButton.one().getName() + '-'
 B2RELEASE = PGButton.getReleasePrefix() + MouseButton.two().getName() + '-'
 B3RELEASE = PGButton.getReleasePrefix() + MouseButton.three().getName() + '-'
+WHEELUP = PGButton.getReleasePrefix() + p3d.MouseButton.wheelUp().getName() + '-'
+WHEELDOWN = PGButton.getReleasePrefix() + p3d.MouseButton.wheelDown().getName() + '-'
 # For DirectEntry widgets
 OVERFLOW = PGEntry.getOverflowPrefix()
 ACCEPT = PGEntry.getAcceptPrefix() + KeyboardButton.enter().getName() + '-'