Run "HelloOverdraw" in apps/toys/Hello. Set the flags as defined in the HelloOverdraw class documentation. Press the number "7", which will toggle the arcWidth / arcHeight of the 7th (top) "russian doll" in the stack of rectangles. It should always be a green overdraw rectangle drawn, as only the top node and/or the top two nodes should ever be drawn, but actually the entire stack is drawn in some cases.

The problem is that Group#computeRenderRoot handles the case of EXISTS_BUT_NOT_DIRTY wrong, because the node associated with EXISTS_BUT_NOT_DIRTY is not added to the NodePath, but should be.