diff --git a/mozilla/layout/style/test/Makefile.in b/mozilla/layout/style/test/Makefile.in
index f24b09f4c14..03066a66b96 100644
--- a/mozilla/layout/style/test/Makefile.in
+++ b/mozilla/layout/style/test/Makefile.in
@@ -74,6 +74,7 @@ _TEST_FILES = 	test_bug302186.html \
 		test_inherit_storage.html \
 		test_initial_storage.html \
 		test_property_database.html \
+		test_property_syntax_errors.html \
 		css_properties.js \
 		property_database.js \
 		$(NULL)
diff --git a/mozilla/layout/style/test/property_database.js b/mozilla/layout/style/test/property_database.js
index 9298e7c6aec..d571d718bbe 100644
--- a/mozilla/layout/style/test/property_database.js
+++ b/mozilla/layout/style/test/property_database.js
@@ -244,7 +244,10 @@ var gCSSProperties = {
 		type: CSS_TYPE_LONGHAND,
 		initial_values: [ "auto" ],
 		other_values: [ "1", "0", "17" ],
-		invalid_values: [ "-1", "3px" ]
+		invalid_values: [
+			// "-1", unclear: see http://lists.w3.org/Archives/Public/www-style/2007Apr/0030
+			"3px"
+		]
 	},
 	"-moz-column-gap": {
 		domProp: "MozColumnGap",
@@ -430,9 +433,14 @@ var gCSSProperties = {
 		backend_only: false,
 		type: CSS_TYPE_TRUE_SHORTHAND,
 		subproperties: [ "background-attachment", "background-color", "background-image", "background-position", "background-repeat", "-moz-background-clip", "-moz-background-inline-policy", "-moz-background-origin" ],
-		initial_values: [ "transparent", "none", "repeat", "scroll", "0% 0%", "top left", "left top", "transparent none", "top left none", "none 0% 0%", "transparent none repeat scroll top left", "left top repeat none scroll transparent"],
+		initial_values: [ "transparent", "none", "repeat", "scroll", "0% 0%", "top left", "left top", "transparent none", "top left none", "left top none", "none left top", "none top left", "none 0% 0%", "transparent none repeat scroll top left", "left top repeat none scroll transparent"],
 		other_values: [ "green", "none green repeat scroll left top", "url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==)", "repeat url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==') transparent left top scroll", "repeat-x", "repeat-y", "no-repeat", "none repeat-y transparent scroll 0% 0%", "fixed", "0% top transparent fixed repeat none", "top", "left", "50% 50%", "center", "bottom right scroll none transparent repeat", "50% transparent", "transparent 50%", "50%" ],
-		invalid_values: [ "50% left", "top 50%" ]
+ 		invalid_values: [
+ 			/* mixes with keywords have to be in correct order */
+ 			"50% left", "top 50%",
+ 			/* bug 258080: don't accept background-position separated */
+ 			"left url(404.png) top", "top url(404.png) left"
+ 		]
 	},
 	"background-attachment": {
 		domProp: "backgroundAttachment",
diff --git a/mozilla/layout/style/test/test_property_syntax_errors.html b/mozilla/layout/style/test/test_property_syntax_errors.html
new file mode 100644
index 00000000000..d31d04b7b60
--- /dev/null
+++ b/mozilla/layout/style/test/test_property_syntax_errors.html
@@ -0,0 +1,51 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+-->
+<head>
+  <title>Test that we reject syntax errors listed in property_database.js</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="property_database.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+<div id="testnode"></div>
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+var gDeclaration = document.getElementById("testnode").style;
+
+for (var property in gCSSProperties) {
+  var info = gCSSProperties[property];
+  for (var idx in info.invalid_values) {
+    var badval = info.invalid_values[idx];
+
+    gDeclaration.setProperty(property, badval, "");
+
+    is(gDeclaration.getPropertyValue(property), "",
+       "invalid value '" + badval + "' not accepted for '" + property +
+       "' property");
+
+    if ("subproperties" in info) {
+      for (var sidx in info.subproperties) {
+        var subprop = info.subproperties[sidx];
+        is(gDeclaration.getPropertyValue(subprop), "",
+           "invalid value '" + badval + "' not accepted for '" + property +
+           "' property when testing subproperty '" + subprop + "'");
+      }
+    }
+
+    gDeclaration.removeProperty(property);
+  }
+}
+
+</script>
+</pre>
+</body>
+</html>
