Hi,
Sorry for the late reply.
1) The $data is used only for populating the table with some sample data when it first started.
2) Once the value for each cell is being loaded, the values for each cell reside in the GtkListStore $model
3) Any changes when you edit the cell are also updated back into the $model
4) To save the value after editing, you need to retrieve the value from the $model.
You may want to refer to the following sample code:
Sample Code 196: How to iterate through a GtkListStore - Part 1?
It will show you how to retrieve the values from the GtkListStore.
Regards,
/kksou