Yes, that was me. Remember?
I have your ACP thing, too, and there are no outstanding patches I've applied.
I have Kitchen Sink 20.0.0. I have had it since you gave it to me.
I disabled EVERY plugin except Kitchen Sink and it still adds a + sign to the URL. This happens in Safari and Chrome, so it's not like it's a browser thing.
Nothing needs patched, and this is 4.2.6.
I don't have many Applications, either, and you moved Kitchen Sink to the top of the plugins list when you had ACP access the last time.