[Solved] How to customize Grid popup window

[Gts]

Hi.
Can I customize grid popup window? For example I want add my control(for example file selection button) to popup window and add some code for them?

[Gts]

And I want add some code for data validation(for example I want look into db and compare entered and exists data and if entered data wrong show message and didn't close window until user fix this data).
I still can't find the way to do this.