diff --git a/components/style/properties/shorthand/mask.mako.rs b/components/style/properties/shorthand/mask.mako.rs
index f71652fac2d..0d07e108d31 100644
--- a/components/style/properties/shorthand/mask.mako.rs
+++ b/components/style/properties/shorthand/mask.mako.rs
@@ -49,10 +49,6 @@
                     if let Ok(value) = input.try(|input| mask_image::single_value
                                                                    ::parse(context, input)) {
                         image = Some(value);
-
-                        // Parse mask mode, if applicable.
-                        mode = input.try(|input| mask_mode::single_value::parse(context, input)).ok();
-
                         continue
                     }
                 }
@@ -70,7 +66,7 @@
                         continue
                     }
                 }
-                % for name in "repeat origin clip composite".split():
+                % for name in "repeat origin clip composite mode".split():
                     if ${name}.is_none() {
                         if let Ok(value) = input.try(|input| mask_${name}::single_value
                                                                                ::parse(context, input)) {
@@ -146,6 +142,10 @@
             }
 
             for i in 0..len {
+                if i > 0 {
+                    try!(dest.write_str(", "));
+                }
+
                 % for name in "image mode position_x position_y size repeat origin clip composite".split():
                     let ${name} = if let DeclaredValue::Value(ref arr) = *self.mask_${name} {
                         arr.0.get(i % arr.0.len())
diff --git a/tests/unit/style/parsing/mask.rs b/tests/unit/style/parsing/mask.rs
index 466f2b24a93..ed655bc844d 100644
--- a/tests/unit/style/parsing/mask.rs
+++ b/tests/unit/style/parsing/mask.rs
@@ -107,12 +107,12 @@ fn mask_shorthand_should_parse_origin_and_clip_correctly() {
 }
 
 #[test]
-fn mask_shorthand_should_not_parse_when_mode_specified_but_image_not() {
+fn mask_shorthand_should_parse_mode_everywhere() {
     let url = ServoUrl::parse("http://localhost").unwrap();
     let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
-    let mut parser = Parser::new("luminance 7px 4px repeat-x padding");
-    assert!(mask::parse_value(&context, &mut parser).is_err());
+    let mut parser = Parser::new("luminance 7px 4px repeat-x padding-box");
+    assert!(mask::parse_value(&context, &mut parser).is_ok());
 
     let mut parser = Parser::new("alpha");
-    assert!(mask::parse_value(&context, &mut parser).is_err());
+    assert!(mask::parse_value(&context, &mut parser).is_ok());
 }