Hmmm. . . It’s not in a clothes’ closet, it’s not a switch, it’s not a receptacle . . . What’s the problem?
Joking aside, where’s the violation? It’s hard to believe, but it appears the NEC has completely overlooked this situation. 408.16 (panelboards) refers us to 312.2 (boxes), which only addresses surface-mounted enclosures. 404.4 (switches) calls for a weatherproof cover, and even allows for “listed shower assemblies.” 550.13 and 552.41 ban receptacles, but this isn’t one of those.
Breakers having “switch ratings” doesn’t make them switches (is a specific breaker actually in use as a switch?) and we locate plenty of disconnects in wet locations.
With the panel being flush mounted, that might actually place it outside the shower enclosure - strictly speaking. After all, we define clearances using the face of cabinet doors, not the enclosed components (Canada is different on this point).
Ironically, the NEC might actually allow a meter / service drop in a shower, but not a light switch.
I am sure this is a DIY ‘home improvement.’ I suspect the window is not of the required safety glass. Wood in a shower is also a bad idea.
On the ‘plus” side, this is one panel that won’t have a ton of flammable junk stored in front of it.