@minna-xD Great catch, I didn't notice that! 👍

There might be another case to consider for the solution: If CurrentUICulture is set to a language not supported by the app (which can happen), we need a fallback to English (similar to the rest of the UI). The simplest options could be to either check if a file Help.<lang-code>.html exists in the Help folder or if the current Culture is part of AppInfo.GetSupportedCultures() (which doesn't depend on the removed attribute). If that's not the case, we would load the English help file.

Would be great if you could try to implement this as well (in case you want to play around with C# a little more 😃). I can help if you need any further guidance.

Sure, I'll give it a go! I was originally thinking about checking if a help file exists and then falling back to English if not, so I'll try that.

I made a new commit yesterday (letting you know in case there's no automatic notification)