Lien, Ruthruff, and Johnston (2010) reported that the attentional control system is able to rapidly and fully switch between different search settings (e.g., red to green), with no carryover. The present study examined whether such impressive flexibility is possible even with more complicated switches, namely singleton search and the feature search. These modes seem particularly incompatible, creating a severe challenge. On each trial, participants were prompted to identify the letter that is uniquely colored (singleton search) or that has a specific color (feature search). The target display was preceded by a non-informative cue display containing an irrelevant color singleton cue. On feature search trials, the irrelevant color singleton cue was able to strongly capture attention (at least for random task sequences), contrary to the typical contingent capture findings. This breakdown indicates a limitation in the sharpness of attentional control, under conditions that might be prevalent in the real world.