Improve calculating the suggestion list's position

[minhhai2209]

Hi. The current method for calculating the suggestion list's position does not work in IE. The problem is that editor.selection.getRng().getClientRects() always returns an empty array. I have just found out that it can be fixed by making a Range with positive length. Here is the new code:

    var range = ed.selection.getRng();
    var rangeStart = range.startOffset;
    range.setStart(range.startContainer, range.startOffset - 1);
    var rects = range.getClientRects();
    range.setStart(range.startContainer, rangeStart);
    if (rects.length > 0) {
      var rect = rects[0];
      textareaTop = rect.top + rect.height;
      textareaLeft = rect.left;
    }