Can't edit Synth V track after sharing Reaper project with friend

I am trying out Synthesizer V Studio 2 Pro using the 14-day trial version, which I downloaded a couple of days ago.

I created a Reaper project with a couple of Synthesizer V tracks (plus other content). I shared the Reaper project with a friend, who does not have the Synthesizer V VST installed. He made some changes to some of the other tracks, then saved a new version of the Reaper project and sent it back. When I opened the new version I found that I cannot edit the existing tracks in the Synthesizer V VST UI. The arrangement and piano roll for the VST do not respond to mouse clicks - although I can click on menus at the top.

Any ideas for how I can recover the ability to edit the existing Synthesizer V tracks?

I only work with Cubase; I’m not familiar with Reaper.

Can you save the project somewhere on your system using the “Save as” option in the menu? Then create a fresh, new, second instance of Synth V and load your previously saved project there under “Open.” If that works, you can delete the first, older instance. That’s how I always do it when there are problems with the VST instrument in Synthesizer V Pro.