diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index 8cb0fdf11f00..cc8f4e4a474f 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -2624,6 +2624,7 @@ function UpdateUrlbarSearchSplitterState()
       splitter.id = "urlbar-search-splitter";
       splitter.setAttribute("resizebefore", "flex");
       splitter.setAttribute("resizeafter", "flex");
+      splitter.setAttribute("skipintoolbarset", "true");
       splitter.className = "chromeclass-toolbar-additional";
     }
     urlbar.parentNode.insertBefore(splitter, ibefore);
diff --git a/toolkit/content/tests/chrome/Makefile.in b/toolkit/content/tests/chrome/Makefile.in
index 6bf709855304..85e6d1eea8f3 100644
--- a/toolkit/content/tests/chrome/Makefile.in
+++ b/toolkit/content/tests/chrome/Makefile.in
@@ -109,10 +109,6 @@ _TEST_FILES = 	findbar_window.xul \
 		RegisterUnregisterChrome.js \
 		test_panel.xul \
 		window_panel.xul \
-		$(NULL)
-
-
-_TEST_FILES +=  \
 		test_bug360220.xul \
 		test_bug365773.xul \
 		test_bug382990.xul \
@@ -122,6 +118,7 @@ _TEST_FILES +=  \
 		test_bug554279.xul \
 		test_bug557987.xul\
 		test_bug562554.xul \
+		test_bug585946.xul \
 		test_button.xul \
 		test_closemenu_attribute.xul \
 		test_colorpicker_popup.xul \
diff --git a/toolkit/content/tests/chrome/test_bug585946.xul b/toolkit/content/tests/chrome/test_bug585946.xul
new file mode 100644
index 000000000000..738e46b1b1d2
--- /dev/null
+++ b/toolkit/content/tests/chrome/test_bug585946.xul
@@ -0,0 +1,51 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<window title="Toolbar" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="startTest();">
+
+  <script type="application/javascript" src="chrome://mochikit/content/MochiKit/packed.js"></script>
+  <script type="application/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <toolbox>
+    <toolbarpalette/>
+    <toolbar id="toolbar" defaultset="node1,node2">
+      <toolbarbutton id="node1" label="node1" removable="true"/>
+      <toolbarbutton id="node2" label="node2" removable="true"/>
+    </toolbar>
+  </toolbox>
+
+  <!-- test resuls are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml"
+        style="height: 300px; overflow: auto;"/>
+  
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+function startTest() {
+  var toolbar = $("toolbar");
+
+  var splitter = document.createElement("splitter");
+  splitter.setAttribute("id", "dynsplitter");
+  splitter.setAttribute("skipintoolbarset", "true");
+
+  toolbar.insertBefore(splitter, $("node2"));
+
+  function checkPos() {
+    is($("dynsplitter").previousSibling, $("node1"));
+    is($("dynsplitter").nextSibling, $("node2"));
+  }
+
+  checkPos();
+  toolbar.style.MozBinding = "url(chrome://global/content/bindings/toolbar.xml#toolbar-drag)";
+  toolbar.clientTop; // style flush
+  checkPos();
+
+  SimpleTest.finish();
+}
+
+  ]]></script>
+</window>
diff --git a/toolkit/content/widgets/toolbar.xml b/toolkit/content/widgets/toolbar.xml
index ad15ac8600ee..9b6835a7a2ff 100644
--- a/toolkit/content/widgets/toolbar.xml
+++ b/toolkit/content/widgets/toolbar.xml
@@ -180,6 +180,9 @@
         <parameter name="aNode"/>
         <body>
         <![CDATA[
+          if (aNode.getAttribute("skipintoolbarset") == "true")
+            return "";
+
           switch (aNode.localName) {
             case "toolbarseparator":
               return "separator";
@@ -213,6 +216,9 @@
 
         <setter>
           <![CDATA[
+            if (val == this.currentSet)
+              return;
+
             var ids = (val == "__empty") ? [] : val.split(",");
 
             var nodeidx = 0;
