diff --git a/toolkit/content/widgets/tabbrowser.xml b/toolkit/content/widgets/tabbrowser.xml
index 4cdeaa67783..410a9646fa3 100644
--- a/toolkit/content/widgets/tabbrowser.xml
+++ b/toolkit/content/widgets/tabbrowser.xml
@@ -583,12 +583,13 @@
             // If location bar is hidden and the URL type supports a host,
             // add the scheme and host to the title to prevent spoofing.
             // XXX https://bugzilla.mozilla.org/show_bug.cgi?id=22183#c239
+            // (only for schemes that support a host)
             try {
               if (docElement.getAttribute("chromehidden").indexOf("location") != -1) {
-                var host = this.mURIFixup.createExposableURI(
-                             this.mCurrentBrowser.currentURI).prePath;
-                if (host)
-                  newTitle = host + sep + newTitle;
+                var uri = this.mURIFixup.createExposableURI(
+                            this.mCurrentBrowser.currentURI);
+                if (uri.host)
+                  newTitle = uri.prePath + sep + newTitle;
               }
             } catch (e) {}
                         
diff --git a/xpfe/appshell/src/nsContentTreeOwner.cpp b/xpfe/appshell/src/nsContentTreeOwner.cpp
index aa93e86171a..fd9b6f9a2ae 100644
--- a/xpfe/appshell/src/nsContentTreeOwner.cpp
+++ b/xpfe/appshell/src/nsContentTreeOwner.cpp
@@ -639,9 +639,12 @@ NS_IMETHODIMP nsContentTreeOwner::SetTitle(const PRUnichar* aTitle)
               nsCOMPtr<nsIURI> tmpuri;
               nsresult rv = fixup->CreateExposableURI(uri,getter_AddRefs(tmpuri));
               if (NS_SUCCEEDED(rv) && tmpuri) {
+                // (don't bother if there's no host)
+                nsCAutoString host;
                 nsCAutoString prepath;
+                tmpuri->GetHost(host);
                 tmpuri->GetPrePath(prepath);
-                if (!prepath.IsEmpty()) {
+                if (!host.IsEmpty()) {
                   //
                   // We have a scheme/host, update the title
                   //
diff --git a/xpfe/global/resources/content/bindings/tabbrowser.xml b/xpfe/global/resources/content/bindings/tabbrowser.xml
index 606dafe87e8..6ba05191040 100644
--- a/xpfe/global/resources/content/bindings/tabbrowser.xml
+++ b/xpfe/global/resources/content/bindings/tabbrowser.xml
@@ -511,12 +511,13 @@
             // If location bar is hidden and the URL type supports a host,
             // add the scheme and host to the title to prevent spoofing.
             // XXX https://bugzilla.mozilla.org/show_bug.cgi?id=22183#c239
+            // (only for schemes that support a host)
             try {
               if (docElement.getAttribute("chromehidden").indexOf("location") != -1) {
-                var host = this.mURIFixup.createExposableURI(
-                             this.mCurrentBrowser.currentURI).prePath;
-                if (host)
-                  newTitle = host + sep + newTitle;
+                var uri  = this.mURIFixup.createExposableURI(
+                             this.mCurrentBrowser.currentURI);
+                if (uri.host)
+                  newTitle = uri.prePath + sep + newTitle;
               }
             } catch (e) {}