Unable to replace software instrument with sampler
I'm trying to add the sampler in place of an instrument in GarageBand. In Apple's documentation (and other online tutorials) it advises to navigate to the smart controls tab of an instrument and then click the instrument to reveal a dropdown where I should be able to select the au sampler.
I'm clicking the blue dropdown (shown below) and nothing is happening though. Is this a bug with this version of the software, and if so is there an alternative way to add the sampler?
I'm using Mac OS Sierra 10.13.4, Garageband 10.2.0, MacBook Pro (15-inch, 2017).
GarageBand 10, macOS High Sierra (10.13.4)