Here's the Fix:
sb.AppendLine ("function " + ClientID + "SplitterDrag(e) {");
sb.AppendLine ("if(e == null) var e = event;");
if (Controller.IsRightToLeft)
sb.AppendLine("var __delta = __clientX - e.clientX;");
else
sb.AppendLine("var __delta = e.clientX - __clientX;");
sb.AppendLine("if((__folderTreeWidth + __delta) > 0) {");
sb.AppendLine("WebForm_SetElementWidth(__fileView, __fileViewWidth - __delta);");
sb.AppendLine("WebForm_SetElementWidth(__folderTree, __folderTreeWidth + __delta);");
sb.AppendLine("}");
sb.AppendLine("return false;");
sb.AppendLine ("}");
Cheer's