It seems the playback bar is not in sync with the mouse movement event and shows very inconsistent behaviors in TV mode.
1) click play DVD directly from the root menu, most times the playback bar won't even display at all.
2) during bluray playback, change the sound output source (from bluetooth speakers to headphones or HDMI out), the playback bar will stuck onscreen forever
3) in the past, when the playback bar displays in the bottom, the top menu bar (back botton on top left, switch mode, minimize, maximize, close bottons on the top right) will always be in synced with the playback bar. They either display together or disappear together. In 2406, they appear to be out-of-sync sometimes.
Work around:
To make the top menu bar and botoom playback bar in sync and auto hide after mouse movement, you can move (hover over) the mouse cursor to one of the 3 buttons in the top menu bar (min, max, close). don't click, just hover over for 2 seconds or so, both menu bars will be in sync and auto hide afterwards. It seems hover over triggers the sync and auto hide events, however, the old mouse idle event along won't trigger auto hide consistently.
I am using Windows 10 Pro x64 1607, GTX 1070 over HDMI 2.0 or DP 1.2 on 4K@60Hz monitor. My DPI setting is at 200%