Incompaitible mixin of MouseHandler

[Yefancy]

https://github.com/ReplayMod/jGui/blob/master/src/main/java/de/johni0702/minecraft/gui/versions/mixin/MixinMouseListener.java#L21-L22

@Mixin(Mouse.class)
public abstract class MixinMouseListener {
    @Accessor // Note: for some reason Mixin doesn't include this in the refmap json if it's just a @Shadow field
    abstract int getActiveButton();
}

this is incompatible with accessors from other mods. Because this access permission is only for the protected method.
if any other mixin attempts to do the same like

@Mixin(Mouse.class)
public interface MouseHandlerAccessor {
    @Accessor int getActiveButton();
}

they will throw an exception when accessing it (even code impl here is recommned from mixin doc)

I notice that you said you are not allowed to use @Shadow here you. but you'd better use your own method instead, if you want to keep it protected.

@Mixin(Mouse.class)
public abstract class MixinMouseListener {
    @Accessor( "activeButton")
    abstract int jgui$getActiveButton();
}