For instance Portallayout.setPanel(panel,0,0) should add panel as first child (first column, first row).
But it doesn't if there is already a child in first column.

in Portallayout.java:
public boolean setPanel(Panel panel, int col, int row)
{
...
if(children.getChildren().size() >= row)

should be:

if(children.getChildren().size() <= row)