Grouped Header Column size

[direct2kali]

I have a grouped header grid. The grid definition can be found in the fiddle http://jsfiddle.net/7sZge/

The result looks like this.

notworkinggrid.jpg

I want all the columns to be of equal space, including the ones inside the grouped header. What am I doing wrong?

[scottmartin]

Duplicate post:
http://www.sencha.com/forum/showthread.php?242430