diff --git a/suite/browser/navigator.xul b/suite/browser/navigator.xul
index 877b8f370a..5b059fcda8 100644
--- a/suite/browser/navigator.xul
+++ b/suite/browser/navigator.xul
@@ -262,7 +262,7 @@
                  enablehistory="true" accesskey="&locationBar.accesskey;"
                  defaultSearchEngine="true" tabscrolling="true"
                  showcommentcolumn="true"
-                 inputtooltiptext="&locationBar.tooltip;"
+                 placeholder="&locationBar.tooltip;"
                  newlines="stripsurroundingwhitespace"
                  aria-label="&locationBar.title;"
                  oninput="gBrowser.userTypedValue = this.value;"
diff --git a/suite/browser/urlbarBindings.xml b/suite/browser/urlbarBindings.xml
index 0bb2d20240..4e1bea68a6 100644
--- a/suite/browser/urlbarBindings.xml
+++ b/suite/browser/urlbarBindings.xml
@@ -25,11 +25,13 @@
             <xul:image class="autocomplete-icon" allowevents="true"/>
           </children>
 
-          <xul:hbox class="textbox-input-box paste-and-go" flex="1" xbl:inherits="context,tooltiptext=inputtooltiptext">
+          <xul:hbox class="textbox-input-box paste-and-go" flex="1" tooltip="_child" xbl:inherits="context">
             <children/>
             <html:input anonid="input" class="autocomplete-textbox textbox-input"
                         allowevents="true"
-                        xbl:inherits="tooltiptext=inputtooltiptext,value,type,maxlength,disabled,size,readonly,placeholder,tabindex,accesskey,mozactionhint,userAction"/>
+                        xbl:inherits="value,type,maxlength,disabled,size,readonly,placeholder,tabindex,accesskey,mozactionhint,userAction"/>
+            <xul:tooltip anonid="tooltip"
+                         onpopupshowing="document.getBindingParent(this)._showTooltip(event);"/>
           </xul:hbox>
           <children includes="hbox"/>
         </xul:hbox>
@@ -47,7 +49,7 @@
       <children includes="menupopup"/>
     </content>
 
-    <implementation>
+    <implementation implements="nsIDOMEventListener">
       <constructor><![CDATA[
         this.mPrefs.addObserver("browser.urlbar", this.mPrefObserver, false);
 
@@ -56,9 +58,13 @@
         this.updatePref("browser.urlbar.showSearch");
         this.updatePref("browser.urlbar.formatting.enabled");
         this.inputField.controllers.insertControllerAt(0, this._editItemsController);
+        this.inputField.addEventListener("overflow", this, false);
+        this.inputField.addEventListener("underflow", this, false);
       ]]></constructor>
 
       <destructor><![CDATA[
+        this.inputField.removeEventListener("underflow", this, false);
+        this.inputField.removeEventListener("overflow", this, false);
         this.inputField.controllers.removeController(this._editItemsController);
         this.mPrefs.removeObserver("browser.urlbar", this.mPrefObserver);
       ]]></destructor>
@@ -96,6 +102,35 @@
         ]]></body>
       </method>
 
+      <field name="_overflowing">false</field>
+
+      <method name="handleEvent">
+        <parameter name="aEvent"/>
+        <body><![CDATA[
+          switch (aEvent.type) {
+            case "overflow":
+              this._overflowing = true;
+              break;
+            case "underflow":
+              this._overflowing = false;
+              break;
+          }
+        ]]></body>
+      </method>
+
+      <method name="_showTooltip">
+        <parameter name="aEvent"/>
+        <body><![CDATA[
+          var tooltip = aEvent.target;
+          if (this._overflowing)
+            tooltip.label = this.value;
+          else if (this.value)
+            tooltip.label = this.placeholder;
+          else
+            aEvent.preventDefault();
+        ]]></body>
+      </method>
+
       <field name="_formattingEnabled">true</field>
 
       <method name="_formatValue">
