(Moving from #278036) Discover lacks scrollbars on the left side of the screen. The only way to scroll is with a scrollwheel. Not particularly important, but inconsistent with other KDE Applications.
It's possible to click and drag the window, then the scrollbars will appear. However this seems like leftovers from a phone-like UX which should not be present in "desktop mode".
this will be fixed with Plasma 5.11 release