Halion 6 window disappears when dragging fxp file onto Slot Rack

I purchased a 3rd party VST instrument, and while the support info is admittedly very sparse, the programmer even sent me a video of how to drag/drop the fxp file onto the Slot Rack to load it into Halion. Every time I try to do this, however, the Halion window disappears, either completely or underneath the other Cubase windows. I am unable to load this instrument - - - unless there is a better way to ‘install’ it to get Cubase to recognize it upon boot-up (i.e. best path/folder to copy the fxp to?) I’m not terribly tech-oriented though I have just enough knowledge after using this program for years to screw myself up!!! This is the first 3rd party VST that I have had trouble with but the behavior of Halion (or Cubase?) seems incorrect to me, no idea why a window should disappear when trying to drag a file onto it from a Windows File Explorer window…it worked in the VST guy’s video just fine. Any info? Thanks.

Bump - can anyone advise how to stop the Helion window from disappearing when dragging an .fxp file onto it, or alternately, advise in which directory is best to put this .fxp to get Cubase (Pro 10.5) to read it on launch? It’s the INIL Choir (from 10cc’s “I’m Not In Love”) from Sampletech out of Sweden, they’ve not been very helpful despite sending me instructions & a video on how to drag it onto Halion, while I’m saying I CAN’T drag it onto Halion! So they’ve stopped responding & I have a plugin that I can’t use. Anyone? Thanks.

Bump again - has nobody had this difficulty with any VST? Is it just a faulty program or could I copy the fxp file to a directory? And if so, which one? I need this plugin for a project. Thanks.