Regarding combo box multiple selections in a power apps gallery

[Rhk]

So I was trying to store a multiple selected values in a combo box inside a gallery

so OnChange I gave a code which lookup the current ID of the item and then it updates the multiple selected value there. 
on OnChange 

patch(

list_name,

lookup(

list_name, ID = Thisitem.ID),

{
column_name : Combobox3.selecteditems

})

And on DefaultSelectedItem

ThisItem.Column_name

[Rhk]

@WarrenBelz can you comment your input on this?