Make sure widgets are added to vertical scroll size

Closes #1148

Author: marijnh

lib/codemirror.js

@@ -3608,7 +3608,7 @@ window.CodeMirror = (function() {
 
   function widgetHeight(widget) {
     if (widget.height != null) return widget.height;
-    if (!widget.node.parentNode)
+    if (!widget.node.parentNode || widget.node.parentNode.nodeType != 1)
       removeChildrenAndAdd(widget.cm.display.measure, elt("div", [widget.node], null, "position: relative"));
     return widget.height = widget.node.offsetHeight;
   }
@@ -3619,8 +3619,12 @@ window.CodeMirror = (function() {
     changeLine(cm, handle, function(line) {
       (line.widgets || (line.widgets = [])).push(widget);
       widget.line = line;
-      if (!lineIsHidden(line) || widget.showIfHidden)
+      if (!lineIsHidden(line) || widget.showIfHidden) {
+        var aboveVisible = heightAtLine(cm, line) < cm.display.scroller.scrollTop;
         updateLineHeight(line, line.height + widgetHeight(widget));
+        if (aboveVisible)
+          setTimeout(function() {cm.display.scroller.scrollTop += widget.height;});
+      }
       return true;
     });
     return widget;