How to queue the invocation of a slot instead of calling directly ?

The closest you can do is create a Timer object with a timeout of 1 millisecond (actually, 0 might work, not sure), and invoke the function in the onTriggered / onTimeout or whatever it’s called, handler. @ Agreed, without adding additional underlying code this is probably the best solution. An interval of 0 works for this too, in my experience.