What is the command produced when long-pressing the OK button on the Roku remote?

I recently encountered a problem which led me to delete and redefine the Roku  to the Harmony Hub. As a result, I redefined the keys on the Harmony remote, including the long-press of the OK button (defined it as “ok”), and now long-pressing OK while  viewing the TV channel list via the Spectrum app brings up the sort and filter view just as does the long-press on the Roku remote.