Active Assembly search in Rx6.5.2

We have had a request to change the appearance of the search box that comes up when adding related content in Active Assembly - specifically they want the default tab to be ‘Search’ i.e. it is the active tab when the search box opens.

How easy is it to make such a change and is there anything in the documentation to help reconfigure the search box? Has anyone made changes to the search box already? If so, their input would be helpful as a starting point.

If this is a difficult and complex task, please let me know and I can let the users know accordingly.