There are inherent and consistent FX bugs in 1.8.3 and prior versions. In any of my projects (old or new from scratch), when attempting to re-adjust or add a style, I am occasionally unable to choose any of the style categories again (the option of choosing a category freezes in the reopened panel) without having to first reboot Designer. This happens in Photo 1.8.3 as well. Also, when copying and pasting FX styles from one object to another, the style measurements often (bevel size, outer shadow, etc.) end up slightly altered from the original source. Hope I am not the only one having similar issues.
iMac (Retina 5K, 27-inch, 2019), 3.7 GHz 6-Core Intel Core i5, 64 GB Ram, Radeon Pro 580X 8 GB
