need at least 1x1 px space to receive focus

Author: ivaynberg

select2.css

@@ -616,12 +616,12 @@ disabled look for disabled choices in the results dropdown
 .select2-offscreen {
     border: 0;
     clip: rect(0 0 0 0);
-    height: 0;
+    height: 1;
     margin: 0;
     overflow: hidden;
     padding: 0;
     position: absolute;
-    width: 0;
+    width: 1;
     display:block;
     left: -10000px;
 }