Yesterday I installed Solus Plasma, everything was fine until I run my first full system upgrade and I noticed that the solus-dark plasma style (the theme that affects the panel and widgets) is missing the mouse hover effect (blue background highlight), as shown in this video:
Note that the light theme is working fine. That highlight effect is also applied when navigating with the keyboard arrows, its very difficult to navigate without a visual feedback. The bug also affects hidden icons in the system tray and the alternative application menus.