Add blank line to top of combobox

Question

I have a combobox showing all security groups in alphabetic order, the code used is:

$groups = Get-ADGroup -Filter 'GroupCategory -eq "Security"' | Select-Object -Expand name | sort-object 
$editusersecgroupentrybox.DataSource = $groups

This is part of a GUI used by the service desk to add users to groups.
I need to have the top line blank to prevent accidentally adding users to the first group in the list.
How can I add a blank line to the top of this?

Answer 1

You asked this on your previous post. I provided an answer (and an example) there.