I’m building a service to be used by a CustomSelector that returns a list which includes a thumbnail. The thumbnail seems to be limited to 32px in size, which is not optimal for our case. Is it possible to increase the size of thumbnail, e.g. to make it look like the list presented in ImageSelector?
Thumbnail size in Custom and Content selectors is limited to preserve layout of the dropdown. What you are basically asking about is alternative layout mode in the Custom selector dropdown, like the one in Image selector. This is doable, but this is a new feature - so I’m moving this issue to Feature requests.