I haven't had that problem here. Mine still works with the window closed. I do have a problem with the presets. In the stand alone version there are way more banks and presets than in the VST version.
Home built i7 6850k Broadwell, 16GB corsair RAM, Asus X99 Deluxe II/Gen 3, EVGA GeForce GTX 1060 6gig, Win 10 creators with no windows updates since jan 2018, Sonar Platinium, Sony Vegas Pro 15, Sound Forge 11, Pro Tools 10, Superior Drummer 3, Easy Keys, Melodyne Studio 4, MOTU 2408, Motu MTPav, midisport 4X4,Behringer X32 Compact with X-Adat and (2) ada8000 strips,Mackie Control Universal, Monitors by JBL, Tannoy, Fostex.