diff --git a/browser/themes/winstripe/browser/browser.css b/browser/themes/winstripe/browser/browser.css
index 0142995b21ca..b902c55d95f6 100644
--- a/browser/themes/winstripe/browser/browser.css
+++ b/browser/themes/winstripe/browser/browser.css
@@ -720,6 +720,7 @@ toolbar[iconsize="small"] #paste-button[disabled="true"] {
 
 #urlbar-spacer {
   visibility: hidden;
+  height: 0px;  /* We just want this widget's horizontal size behavior */
 }
 
 /* ::::: page proxy icon ::::: */