Issues with 3d apps?

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Leaving aside the app hanging that I mentioned in my previous post, since using Synergy (I started with v1 a couple of years ago) I have had one bugbear that I hoped would have been addressed in v3, but wasn't (possibly because it can't be).

I have the server installed on a laptop with a 1440p monitor at 2560 x 1440. The client is on a much higher specced machine, with 2 x RTX 2070 Super and a 34" ultrawide monitor running at 1440p with a resolution of 3440 x 1440. 

The problem is that when I am running any 3d software on the client (Cinema4D, Daz3D etc) the cursor goes into overdrive whenever I try and rotate or transpose an object. Everything else seems fine - I can smoothly move the mouse around the screen, and accurately click on menus, select objects etc , etc, but as soon as I manipulate the object in 3d space it becomes super-sensitive and exaggerates mouse movements exponentially. I noticed the same behaviour when using Microsoft Flight Simulator. It doesn't happen in any other software I use - only those that have a 3d element.

The only way I can get around this is to have a hotkey that locks Synergy to the currently active screen, after which the behaviour goes away. This was also happening when I had a 1080p monitor on the Synergy server and I originally thought it might be because of the disparity in resolutions. I wondered if Synergy was overloaded with handling multiple resolutions when 3d was involved. I tried activating relative mouse moves, but that didn't work. Anyway, upgrading to a 1440p monitor didn't help, or reduce the problems. 

Has anyone else experienced anything similar when using 3d software. Is there any way to resolve the issue without resorting to locking to the active screen?

Thanks for any advice.