Show Column Header on dragging column

i implement the code in GroupableHeader and try to enable the reordering allowed but i have two problems:

1: When dragging a column the header don´t see over the column
2: How restrict the dragged area of the column to prevent the column exit of the columnGroup

I don´t understand why the header don´t see on column dragging, i read the table header api but did not find any solution. Any ideas for solving these problems?

My predecessor also thought that using code they copied off the internet was a good idea...fortunately for my company, I don't

I spent about 4 weeks of my spare time digging through the implementation and comparing it with the default BasicTableHeaderUI figuring out how to reinstate...

Column ordering, including, limiting the grouped columns to there group
Row sorting
Various other bits and pieces

This is a incomplete solution, as I've not yet quite got to the point where when you drag a group and have it show all the columns in the group, but that's within the TableUI

Unfortunately, I can't paste the code, it's over the 3000 character limit, but you can grab a copy from here

A bit more complete solution: JBroTable.

It's based on MadProgrammer's answer. It restricts column dragging out of the group too. And brings some extra features:

Arbitrary number of rows
Natural API for model creation
Generic support for other L&Fs (Windows system L&F, GTK, Nimbus etc.)

Sample model creation:

IModelFieldGroup groups[] = new IModelFieldGroup[] {   new ModelFieldGroup( "A", "A" )     .withChild( new ModelField( "B", "B" ) )     .withChild( new ModelField( "C", "C" ).withRowspan( 2 ) ), // Custom rowspan set.   new ModelFieldGroup( "D", "D" )     .withChild( new ModelField( "E", "E" ) )     .withChild( new ModelField( "F", "F" ) ),   new ModelField( "G", "G" ),   new ModelFieldGroup( "H", "H" )     .withChild( new ModelFieldGroup( "I", "I" )                   .withChild( new ModelField( "J", "J" ) ) )     .withChild( new ModelField( "K", "K" ) )     .withChild( new ModelFieldGroup( "L", "L" )                   .withChild( new ModelField( "M", "M" ) )                   .withChild( new ModelField( "N", "N" ) ) ) };

Result: