This study examined how attentional set mitigates attention capture by onsets occurring between known spatial locations. In Experiment 1 response times increased with the number of onsets that occurred. In Experiment 2 and 3 color was used instead of onset as the task relevant feature. Data collected at the keystroke-level showed delayed response times for keystrokes in only certain positions following an onset. Typing patterns were also found to affect the costs generated by the onsets, implying that task strategies mediated when onsets captured attention. Experiment 4 manipulated the cue types in a 2 phase spatial cuing task. Cues of the same type in both phases yielded faster responses, even though the blocked nature of the trials alerted participants to the upcoming cue type in each phase. This suggests that participants were unable to rapidly shift attentional set.