Hello and welcome to our forums,
Not quite sure why you would like to do that, but you could proceed in two ways here:
1. use the "SQLConnectionDlg"
dialog instead of the "SQLServerConnectionDlg"
However, by doing so, you will need to do everything manually. More information about this can be found in the following article:
Configure MS-SQL Server Connection
2. remove the "Combobox"
control and replace it with an "Editbox"
control, as it is for the "Username"
, for example.