the epic game launcher/client does not get a border/shadow drawn AT ALL. settings are ignored / do not apply like for all other windows.
I am afraid if the application has opted out of the OS theme then it will be opted out of Curtains. You will notice it does not have a shadow without Curtains running either.
Unless epic add an option to support the OS frame there is nothing we can do for that.
there are other applications like spotify, tidal, steam, MS teams which also draw no border and do not adhere to the design standard. not sure, if / how they are fundamentally different. those CAN get a shadow/border with curtains - which would be really the only thing i would need curtains for.
epic window is of class (and in some way it must be a window/frame/... ?)
while e.g. tidal (and teams) is of class
( maybe you could elaborate on how you put shadows/borders on windows. i notice it keeps working even on new windows even when you stopped the curtains service. i would love to be able to have just some registry settings for that or be able to customize the msstyles/theme file. what i really only need - and would prefer not having a background service/tool running for - is : get a border/shadow on
a. all inactive windows,
b. windows without native borders.
e.g. when working in dark mode those dark apps overlap and you dont see where they end, it is really a design flaw. you should also consider this when testing your dark themes. this is really also a ergonomic problem in your dark skins "dark waters"/... )