fix problem that caused refresh to be ignored after unhiding

Author: marijnh

lib/codemirror.js

@@ -601,7 +601,10 @@ var CodeMirror = (function() {
     // determine which DOM updates have to be made, and makes the
     // updates.
     function updateDisplay(changes) {
-      if (!wrapper.clientWidth) return;
+      if (!wrapper.clientWidth) {
+        showingFrom = showingTo = 0;
+        return;
+      }
       // First create a range of theoretically intact lines, and punch
       // holes in that using the change info.
       var intact = changes === true ? [] : [{from: showingFrom, to: showingTo, domStart: 0}];