Scroll 2 different windows synchronously?


I am a huge fan of this app so thank you to the developers for their ongoing work. I have a specific question or request and I don't know if this is possible?

I want to scroll 2 windows synchronously... specifically I have 2 preview windows open with 2 sets of JPEGs and would like to scroll through them together - or even failing scroll just cycle the 2 sets of images side-by-side frame by frame. This is for a research study but I can imagine a similar feature being incredibly useful in writing academic papers and comparing drafts etc... I tried "send keyboard shortcut to specific app" but of course here I need to use 2 windows of the same app.

Now I can get 2 different image viewer programs and open the 2 sets of images and send the shortcut to go to the next image to trigger in the other app and that is a solution. Unfortunately there is some kind of bug that is stopping any keyboard shortcuts I set from triggering - for instance I set a shortcut to send the "right" shortcut to the other app when I trigger it on Preview and weirdly this stops the entire command from working - nothing happens. Ive tried multiple things and it just doesnt do anything... Im not sure if its a bug or Ive just done something very simple wrong so any advice would be appreciated. All I want to do is press DOWN or RIGHT to scroll "next" in the preview app and send the same command as a keyboard shortcut to the other image viewer app Im using (I am on 3.344 and catalina and have restarted the computer etc)

Any help appreciated :slight_smile: