Sidepanel
Lexicon has a second track browser called the Sidepanel. You can open it from the top menu bar ➡ View ➡ Toggle Sidepanel.
The sidepanel lets you view a second list of tracks or playlist at the same time. This is especially useful when going through an older playlist to cherry pick tracks and dragging them into the new playlist.
The sidepanel is available on the Essential and Ultimate plans. You can open it on every page.
Playlists
To open a playlist in the sidepanel, right click any playlist and choose Open in sidepanel. Right clicking a playlist also selects it in the main track browser, so both show the same playlist at first. Then click the playlist you want to see in the main track browser.
To view all tracks in the sidepanel, toggle it twice. Closing the sidepanel resets it to all tracks.
Hotkeys
Cmd+\ (macOS) or Ctrl+\ (Windows and Linux) opens and closes the sidepanel. This is the default on new installs; if you have used Lexicon before, set it under Toggle sidepanel in the hotkey settings.
Holding the ALT button while clicking any playlist will open it in the Sidepanel, if the Sidepanel is visible.
In Artist Cleanup and Genre Cleanup, ALT+Click or OPTION+Click on an artist or genre shows its tracks in the sidepanel, and opens the sidepanel if it is closed.