Yes it is possible, you can add widget to the footer, override the
render() method in Header class. Try the below code.
Header<Student> footer = new Header<Student>(new
ClickableTextCell())
{
@Override
public void render(Cell.Context context, SafeHtmlBuilder sb)
{
sb.appendEscaped(((Student)getValue()).getMark()) ;
}
}
//add footer to the cell table
celltable.addColumn(student , someHeader, footer);
S. Abraham
www.DataStoreGwt.com