Using Windows Forms code in PowerISE causes the ISE to crash

I was testing a colleague's small script which lists VM snapshots from our vCenters, and it uses a Windows Form to get the vCenter name, username & password. It then logs into the vCenter and extracts the required info.

In a PowerShell command line, it works perfectly. In the ISE, the code runs fine until it completes then after about 10 seconds, the ISE freezes. I tried the same code on other Windows servers in our environment and the same happened.

To test if it was code related or not, I have a script which Get-Credential to ask the user for logon details so I modified the code to create a form with the username & password details using labels & textboxes with an OK button. As soon as I ran the code, it froze the ISE. Again if run from the PowerShell command line, works fine.

I tried adding the following to the scripts which did not help:

Add-Type -AssemblyName  Microsoft.VisualBasic,
                        PresentationCore,
                        PresentationFramework,
                        System.Drawing,
                        System.Windows.Forms,
                        WindowsBase,
                        WindowsFormsIntegration

[System.Windows.Forms.Application]::EnableVisualStyles()

I'm using $Form.Dispose()

Linked references:

https://community.spiceworks.com/topic/1367945-powershell-ise-hanging-when-using-forms

https://stackoverflow.com/questions/30808084/using-windows-forms-locks-up-powershell-ise-minutes-after-script-has-terminated

Does anyone know of any fixes for this situation?