Tested latest LG webOS preview and magic remote works but it also needs horizontal scrolling when navigating inside photos,music or other screens. Second issue I have noticed is when playing photos. Going from photo to photo (full screen) the next picture flushes twice before it is displayed in full screen.
Magic remote input lacks a dedicated horizontal scrolling mechanism, using the left/right arrows is the only way to achieve that, though that may change in the future.
We have filed an issue for the flashing when switching photos.