Since "upgrading" to the latest version of Photo, I have found the program so slow that it is virtually unusable. For instance, while doing a simple tutorial practicing outlining something in an image using the pen tool (nothing else open in the program or on the system), when I zoom in the screen image pixelates and hangs for several seconds, then zooms in much farther than I had intended; when I attempt to zoom back out a bit (using Ctrl + mouse wheel), the same thing happens. This is just one example -- the program has been massively slow since I installed the upgrade, degrading operating system response as well as Affinity Photo's performance. (I never had any problem with lagging in the previous version.)
I'm using Windows 10 on desktop, and nothing on my system has changed recently. I'm going to try reinstalling the last version of 1.9 so that I can continue using Affinity Photo.