Salutations!
I created a Jtable instance with multiselect functionality together with your footer extension however in the footer row I found out that the columns are one column short. I checked out the code for my jtable and I guess the missing column is for the checkbox jtable selecting column.
I hope you can check on this and if you need a sample of my code to help you with troubleshooting then I'll provide it.
Thank you very much.