Searching for Mixin method usage does not work from implementation

[SlimerDude]

Given:

mixin Stuff {
    abstract Void method()
}
class StuffImpl : Stuff {
    override Void method() { }
}

If I search for usages of method() from the implementation (SHIFT+CTRL+G) then F4 returns nothing. Instead I have to select / highlight method() on the mixin and search from there.