--- a/browser/themes/gnomestripe/browser/browser.css
+++ b/browser/themes/gnomestripe/browser/browser.css
@@ -1332,17 +1332,17 @@ statusbarpanel#statusbar-display {
   position: static;
   -moz-appearance: none;
   background: -moz-linear-gradient(hsla(0,0%,100%,.2), hsla(0,0%,45%,.2) 1px, hsla(0,0%,32%,.2) 50%);
   background-position: -5px -2px;
   background-repeat: no-repeat;
   background-size: 200%;
   margin: 0;
   padding: 0;
-  -moz-border-image: url(tabbrowser/tab.png) 4 5 3 6 / 4px 5px 3px 6px;
+  -moz-border-image: url(tabbrowser/tab.png) 4 5 3 6 / 4px 5px 3px 6px repeat stretch;
   border-radius: 10px 8px 0 0;
   min-height: 25px; /* reserve space for the sometimes hidden close button */
 }
 
 .tabbrowser-tab:hover,
 .tabs-newtab-button:hover {
   background-image: -moz-linear-gradient(hsla(0,0%,100%,.6), hsla(0,0%,100%,.2) 2px, hsla(0,0%,75%,.2) 50%);
 }

--- a/browser/themes/winstripe/browser/browser.css
+++ b/browser/themes/winstripe/browser/browser.css
@@ -1385,17 +1385,17 @@ richlistitem[type~="action"][actiontype=
 .tabs-newtab-button {
   -moz-appearance: none;
   background: -moz-linear-gradient(hsla(0,0%,50%,.1), hsla(0,0%,37%,.1) 50%);
   background-position: -5px -2px;
   background-repeat: no-repeat;
   background-size: 200%;
   margin: 0;
   padding: 0;
-  -moz-border-image: url(tabbrowser/tab.png) 4 5 3 6 / 4px 5px 3px 6px;
+  -moz-border-image: url(tabbrowser/tab.png) 4 5 3 6 / 4px 5px 3px 6px repeat stretch;
   border-radius: 10px 8px 0 0;
 }
 
 .tabbrowser-tab:hover,
 .tabs-newtab-button:hover {
   background-image: -moz-linear-gradient(hsla(0,0%,100%,.4), hsla(0,0%,75%,.4) 50%);
 }