Just wanted to note that I've seen a lot of people reporting of slow responsiveness in Fences. The threads usually dead-end without followup or success stories.
I tackled the problem tonight. 300 desktop icons probably didn't help, nor does the 4k resolution.
1) Running the Purge .bat file and then reinstalling didn't seem to help immediately.
2) However this did allow me to run two uninstalls of Fences v.2.
3) My original install of Fences Pro was uncovered, (it even opened) but I couldn't uninstall it. To overcome this, I used a Stardock link to have my purchases emailed to me. From there I downloaded and installed Fences Pro (didn't complete successfully because it couldn't talk to Impulse). However, this fixed up my uninstall information for Fences Pro, and I was able to uninstall it.
Completely Fence-Free, I saw that my desktop performance still sucked. Turns out my gaming mouse software had gotten stuck and hadn't been updated in a while. Updating this software (Steelseries Engine) helped a lot with my desktop performance, and even more after I rebooted.
Just wanted to report something that seems to have helped.