How to filter a second LookUp column based on a first LookUp column's value in EditForm

This is an example for the How to filter a second LookUp column based on a first LookUp column's value in EditForm Knowledge Base article. Please refer to the article for the explanation.
Note that the GridView.EditFormPrepared event is used in this example. This event appeared in version 13.2.7.
If you are using previous versions (13.1.x - 13.2.6), create a custom EditForm as described in the Custom Edit Form help topic and use the approach for standalone editors from the How to filter a second LookUp column based on a first LookUp column's value KB article.