Array behaviour difference in PowerShell 2 to PowerShell 3 - powershell

Question

I have observed a difference in behavior between PowerShell 2.0 code and 3.0 code but can't seem to fix it. I am hoping I can get some help. Please see code below.
If you run this in V2 (please change ServerA and ServerB to a server on your network) you will see after selecting and clicking the button, write-host shows them as seperate names. In version 3 the listbox populates it as 1.
$Servers = #()
[array]$ServerstoPing = ("ServerA","ServerB")
# Generate the form
Add-Type -AssemblyName System.Windows.Forms
$Form1 = New-Object system.Windows.Forms.Form
$Form1.Text = "Ping Some Servers"
$Font = New-Object System.Drawing.Font("Calibri",18,[System.Drawing.FontStyle]::regular)
$Fontboxes = New-Object System.Drawing.Font("Lucida Sans",8,[System.Drawing.FontStyle]::regular)
$Fontdate = New-Object System.Drawing.Font("Lucida Sans",11,[System.Drawing.FontStyle]::bold)
$FontProgress = New-Object System.Drawing.Font("Lucida Sans",11,[System.Drawing.FontStyle]::bold)
$Form1.Font = $Font
$Serverlistbox = New-Object System.Windows.Forms.Listbox
$Serverlistbox.Location = New-Object System.Drawing.Size(11,137)
$Serverlistbox.Size = New-Object System.Drawing.Size(200,170)
$Serverlistbox.SelectionMode = "MultiExtended"
$Serverlistbox.font = $Fontboxes
foreach($item in $ServerstoPing){
[void] $Serverlistbox.Items.Add("$item")
}
$Form1.Controls.Add($Serverlistbox)
$SubmitButton = New-Object System.Windows.Forms.button
$SubmitButton.text = "Ping Servers"
$SubmitButton.Location = New-Object System.Drawing.Size(171,305)
$SubmitButton.AutoSize = $True
$Form1.Controls.Add($SubmitButton)
$Form1.StartPosition = "CenterScreen"
$OutputPing = New-Object System.Windows.Forms.TextBox
$OutputPing.MultiLine = $True
$OutputPing.ScrollBars = "Vertical"
$OutputPing.text = "Server ping status will be displayed here once done'."
$OutputPing.font = $Fontboxes
$OutputPing.Location = New-Object System.Drawing.Size(226,40)
$OutputPing.Size = New-Object System.Drawing.Size(200,255)
$Form1.Controls.Add($OutputPing)
$SubmitButton.add_click({
#foreach ($objItem in $ServerstoPing)
foreach ($objItem in $Serverlistbox.SelectedItems)
{
$Servers += $objItem
}
write-host $ServerstoPing
Foreach($server in $servers)
{
ping -n 1 -w 1000 $server | out-null
if($? -eq $true){
write-host ("$server ping success")
}
else
{
write-host ("$server did not respond to ping, not extracting events")
}
}
})
$Form1.ShowDialog()