[Pharo-project] Weird error with halos on a SystemWindow

self world answers nil and then cannot do the displayWorld. Weird for a halomorph. What's wrong here? It is annoying since I was using the halo "red" menu to work with a morph interactively. Ideas? Pharo 1.4 here. doMenu: evt with: menuHandle "Ask hand to invoke the halo menu for my inner target." | menu | self obtainHaloForEvent: evt andRemoveAllHandlesBut: nil. self world displayWorld. menu := innerTarget buildHandleMenu: evt hand. innerTarget addTitleForHaloMenu: menu. menu popUpEvent: evt in: self world.