Status: New Owner: ---- New issue 3562 by richi.mo...@gmail.com: Deferred UI messages executed slowly http://code.google.com/p/pharo/issues/detail?id=3562 Pharo1.2rc1 Latest update: #12313 Processing deferred ui messages seems to be really slow. You can test it by executing this: | rnd | rnd := Random new. 100 timesRepeat: [ WorldState addDeferredUIMessage: [ Morph new openInWorld; center: rnd next @ rnd next * Display extent. ] ]. You'll notice it takes a couple of seconds to finish opening all the morphs, but if you remove the #addDeferredUIMessage: send, it is instantaneous. In Squeak and Etoys both versions are equally fast. I think the bug is in WorldState>>#runStepsMethodsIn:. It seems it only executes one deferred ui message per step. With the implementation below the problem is fixed. WorldState>>#runStepMethodsIn: aWorld "Perform periodic activity inbetween event cycles" | queue nextInQueue| "If available dispatch some deferred UI Message" queue := self class deferredUIMessages. [(nextInQueue := queue nextOrNil) isNil] whileFalse: [ nextInQueue value]. self runLocalStepMethodsIn: aWorld.