Resize colums when adding new Column

I created a Table with an add-button to add new columns

But to fit the columns on the page, i added a script to resize the columns.

It works, but not for the first column????

All other columns are copies of the first, so how is this possible.

Does anyone has an idea and solution?

https://dl.dropboxusercontent.com/u/50711159/test%20resize%20colums.pdf

https://dl.dropboxusercontent.com/u/50711159/test%20resize%20colums.xdp