UAD plugins - strange screen behavior and not closing properly

[Big_al]

Hi all, whenever I close a UAD plugin in Cubase Studio 4 the title bar of the plugin remains on screen and a blank box where the plugin was displayed is still visible. I can then click onto the title bar and drag it around the screen and the only way to get rid of this is to click onto another open app (Mail for example) and then back into Cubase and the windows then disappear. This is only an issue with UAD plugins as all my non UAD plugs close fine, has anyone else encountered this?

Heres a couple of screen grabs showing the issue.

Plugs open
Plugs Closed

Also, I've messaged UAD and I'm still waiting for a reply.

[Mixedup]

I've seen similar behaviour with some (non UAD) J-Bridged 32-bit plug-ins running in Cubase 8 Pro 64-bit. Don't know if that's related...