Append image to wrapper

Append image to wrapper. No more appending to document.
Works with multiple editors. Tested: 3 editors beneath each other on 1 page.

Author: peterkroon

lib/codemirror.js

@@ -168,6 +168,15 @@ window.CodeMirror = (function() {
 
     // Used for measuring wheel scrolling granularity
     d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null;
+    
+    //opera setDragImage hack
+    if (opera) {
+      var img = elt('img');
+		  img.width = '1';
+		  img.height = '1';
+		  img.setAttribute('style','position:fixed; top:0; left:0; right:0');
+	  	d.wrapper.appendChild(img);
+    }
 
     return d;
   }
@@ -1612,8 +1621,9 @@ window.CodeMirror = (function() {
 
     // Use dummy image instead of default browsers image.
     // Recent Safari (~6.0.2) have a tendency to segfault when this happens, so we don't do it there.
+    var img = opera ? cm.display.wrapper.getElementsByTagName('img')[0] : elt('img');
     if (e.dataTransfer.setDragImage && !safari)
-      e.dataTransfer.setDragImage(elt('img'), 0, 0);
+      e.dataTransfer.setDragImage(img, 0, 0);
   }
 
   function setScrollTop(cm, val) {