An ultrasound scanner in a spectral Doppler mode, in which a corresponding two-dimensional (2D) ultrasound imaging mode (e.g., B-mode) image is frozen, is switched temporarily to the 2D-mode in response to a continuous contact on a touchscreen. During the continuous contact, the spectral Doppler mode is interrupted, the 2D-mode image becomes live, and the gate for the spectral Doppler mode may be adjusted by a movement of the continuous contact on the touchscreen. Upon termination of the continuous contact, the system reverts back to the spectral Doppler mode, which now operates within the adjusted gate, and the 2D-mode image is frozen. A brief contact may be used to check the position of the gate against a live 2D-mode image without adjusting it.