In dhtmlxlayout,dhtmlxwindow can't be show,why?

In dhtmlxlayout,dhtmlxwindow can’t be show,why? The same code work correctly in normal jsp file without dhtmllayout.

dhtmlxWindows can be shown in dhtmlxLayout’s cell.
You should do the following:
1. Create an object on the page;
2. Attach it to layout’s cell;
3. Create a new instance of dhtmlxWindows;
4. Attach viewport to object inserted into layout’s cell.