function ieInternalDragAndDrop() {
			editor.on('dragstart', function(e) {
				setMceInternalContent(e);
			});

			editor.on('drop', function(e) {
				if (!isDefaultPrevented(e)) {
					var internalContent = getMceInternalContent(e);

					if (internalContent && internalContent.id != editor.id) {
						e.preventDefault();

						var rng = RangeUtils.getCaretRangeFromPoint(e.x, e.y, editor.getDoc());
						selection.setRng(rng);
						insertClipboardContents(internalContent.html);
					}
				}
			});
		}
IE cannot set custom contentType's on drag events, and also does not properly drag/drop between
editors. This uses a special data:text/mce-internal URL to pass data when drag/drop between editors.