Currently, the only way to invoke the Brush picker involves having to click on a 16x16 pixel swatch within a wider Property Input/readout.

Although we are used to this internally, it makes it harder to discover (and harder to explain how to invoke it).

As far as I can tell, there is never any other input or clicks possible along the span of this Property Value readout, so we may want to consider making the whole Property Value field clickable to help ease this issue.