Regarding Customized context menu with a new grid in a dialog box

 Hi Team,
I have a scenario where, I am suppose to edit the grid in a dialog box. But the problem is when I double click to edit it, it is getting open in a New "Details" dialog box, instead editing the same cell with in 1st dialog box gird itself. Could you please help me to achieve this ?
I have see the example - https://s3.amazonaws.com/flexmonster/fisglobal/FLEXMONSTER-2018-FIS-MAY23.zip. But I also have done the same options: {editing: true } with the datasource. But still getting open in another "Details" dialog window.
Json String-
 var demo = {
dataSource: {
 data: fetchRows()
},
options: {
 editing: true
}
}