Menus in ManyCam are super slow

All Menues in ManyCam are super slow and unresponsive on my Mac BigSur 11.2.1 ( MacBook Pro 16", 2019/2,3 GHz 8-Core Intel Core i9/64 GB/ AMD Radeon Pro 5500M 8 GB/Intel UHD Graphics 630 1536 MB)
It often leads to operating errors when I want to select layers, select dropdowns, close windows etc.

How can a program respond so slowly?