"...but this control must be delete."
How's that again?
There are several ways a script can use Get ( UserName ) to select the correct layout for that user.
If [Get ( UserName ) = "Fred" ]
Go To layout [ //specify the right layout for "Fred"]
Else If [ Get ( UserName ) = "George"]
//and so forth
is a crude, but simple way to do this.
Better is to set up a user preferences table where you store the user name in one field and use additional fields to store other data that customize your solution's look and feel to the needs of each user. A field in this layout can store the layout name or number and then your script can find this record and use the value in this field to select the appropriate layout. (and set the desired view, find records for this user, etc.)
If you use a global field to relate your main table to this preferences table like this:
MainTable::gUserName = Preferences::UserName
Then your script to select a layout might look like this:
Set Field [MainTable::gUserName ; Get ( UserName ) ]
Go To Layout [Preferences::LayoutName] //Use the "layout name by calculation option here
This second approach allows you to manage system behavior for your user base without needing to modify your script each time a new user name is added to your system.