Update the activeLine on fold changes.

lib/ace/editor.js

@@ -381,6 +381,9 @@ var Editor =function(renderer, session) {
     };
 
     this.onChangeFold = function() {
+        // Update the active line marker as due to folding changes the current
+        // line range on the screen might have changed.
+        this.$updateHighlightActiveLine();
         // TODO: This might be too much updating. Okay for now.
         this.renderer.updateFull();
     };