Slow rendering after scrolling large directory in Windows

First, loving fman! It's a joy to use. Thanks for all the time you've put into it. I bought a license right away.

I've noticed a significant performance difference on Windows vs Linux. I have both installed on the same computer with access to the same hard drives, and fman on Linux performs much faster when it comes to launching and displaying the contents of directories with lots of files.
I wanted to try to narrow down a single repeatable difference between the two and found something interesting.
When I launch fman on Windows, performance starts out great and then slows over time. Here's how you can (hopefully) reproduce. I was able to reproduce on two very different windows machines.

Go to a folder with lots of files. Now just hold down the down arrow until you get to the bottom. Notice how long it takes. In the directory I'm testing, it takes about 12 seconds to get to the bottom. Now hold the up arrow until you get to the top. if it's like mine, you'll notice it's slower. After doing this up and down a few times, it took 22 seconds to get to the bottom. This slowdown affects every other folder I navigate to now. The only way to fix it is to restart fman.

I wonder what could be causing this degradation in performance just from scrolling up and down in a directory. I wasn't able to detect any slow down when trying the same thing on linux.

A couple notes:

I'm wondering if it's a drawing issue of some sort, since the speed it takes to scroll varies significantly depending on the size I've made the fman window.

As I'm scrolling, I can see a single core of the processor working hard on something. That core is nearly maxed out.

No source files or tests are identified in the report. First reproduce the slowdown in fman on Windows by scrolling repeatedly through a directory with many files, then compare it with Linux while monitoring CPU usage and window-size effects. Done means repeated scrolling no longer degrades performance or requires restarting fman.