Bug 456595 - Plain readonly textboxes should have a transparent background. r=Enn.

toolkit/themes/gnomestripe/global/textbox.css

@@ -97,6 +97,7 @@ textbox[disabled="true"] {
 
 textbox.plain {
   -moz-appearance: none !important;
+  background-color: transparent;
   padding: 0px !important;
   margin: 0px !important;
   border: none !important;

toolkit/themes/pinstripe/global/textbox.css

@@ -110,6 +110,7 @@ textbox[disabled="true"] {
 
 textbox.plain {
   -moz-appearance: none !important;
+  background-color: transparent;
   padding: 0px !important;
   margin: 0px !important;
   border: none !important;

toolkit/themes/winstripe/global/textbox.css

@@ -97,6 +97,7 @@ textbox[disabled="true"] {
 
 textbox.plain {
   -moz-appearance: none !important;
+  background-color: transparent;
   padding: 0px !important;
   margin: 0px !important;
   border: none !important;