In a form there's datasource, the datasource content is a table. this table is the datasource of a grid. then I have markChange override method on the table to do business logic when I'm selecting record/s on the grid.
Now the question is, if my form datasource is a Query how could I do the markChange event?
If you add a query to your datasources node of your form it should expand with all the tables in the query.
On the first table you can just override the markChanged method and it will be triggered when you select a record using the checkbox.
The markChanged is triggered on the first table though, not on the others.
