diff --git a/dlls/comctl32/toolbar.c b/dlls/comctl32/toolbar.c
index b417808d806..8a6b8fca457 100644
--- a/dlls/comctl32/toolbar.c
+++ b/dlls/comctl32/toolbar.c
@@ -3026,6 +3026,8 @@ TOOLBAR_GetButton (HWND hwnd, WPARAM wParam, LPARAM lParam)
     lpTbb->idCommand = btnPtr->idCommand;
     lpTbb->fsState   = btnPtr->fsState;
     lpTbb->fsStyle   = btnPtr->fsStyle;
+    lpTbb->bReserved[0] = 0;
+    lpTbb->bReserved[1] = 0;
     lpTbb->dwData    = btnPtr->dwData;
     lpTbb->iString   = btnPtr->iString;