I use my PC mostly with two screens (WQHD on primary, FHD on secondary) and when I run Spotify in single screen mode and I click on the Equalify button it does simply not show up. I have to activate my second screen where the window appears immediately. Once I move the Equalify Window to primary monitor everything works out perfectly.
It seems the last position of the Equalify window remains saved even though there is no 2nd screen. This should be updated.
Win10 incl. all updates and drivers up to date
Equalify Pro version
220.127.116.1109 (latest), just checked for updates
Any special software or hardware you might have installed: