Coordinating multiple effectors, such as the eyes and hands, is essential in many daily activities. While using two effectors simultaneously is typically more demanding than using one (dual-action costs), a prepotent action (e.g., a saccadic eye movement) can interfere with the isolated execution of another response (e.g., a manual keypress). This interference often manifests as frequent false-positive responses in the non-required but prepotent effector. This study examined whether such responses are primarily stimulus-driven (automatically triggered by a suitable stimulus) or response-driven (dependent on a concurrently executed, highly compatible action). Participants responded to a peripheral visual stimulus with (a) a single saccade, (b) a single keypress, (c) both, or (d) no action. Faster saccades in dual-action trials compared to single-saccade trials, and equally fast manual responses in single- and dual-action trials (i.a. absence of dual-action costs), indicated difficulties in separating responses. Critically, false-positive saccades (keypresses) occurred more often in single-manual (single-saccade) trials than in no-action trials, with a stronger tendency for false-positive saccades compared to keypresses overall. These findings suggest that response-driven co-activation between highly compatible actions can complement automatic stimulus-driven activation in generating (unwanted) behavior.