diff --git a/gfx/src/thebes/nsThebesRenderingContext.cpp b/gfx/src/thebes/nsThebesRenderingContext.cpp
index c3233d7e20b5..63e2ae2294f3 100644
--- a/gfx/src/thebes/nsThebesRenderingContext.cpp
+++ b/gfx/src/thebes/nsThebesRenderingContext.cpp
@@ -237,6 +237,7 @@ nsThebesRenderingContext::SetTranslation(nscoord aX, nscoord aY)
     mat->ToValues(&a, &b, &c, &d, &tx, &ty);
     gfxMatrix newMat(a, b, c, d, aX, aY);
     mThebes->SetMatrix(&newMat);
+    return NS_OK;
 }
 
 NS_IMETHODIMP