tempoup tempodown not working on my Windows machine.

Im trying to make use of the PlayerControl(tempoup) function but it doesn’t seem to work with my clean Kodi installation. As I understand the left and right alt by default should speed up or slow down the video when playing it in fullscreen (or just playing a video?) but nothing happens when i press those keys while watching a local video file or SMB video file. i’ve tried .mp4 / mkv h264 and even a rmvb Tongue
I even tried to make custom mapping using the following file.
<keymap>
<FullscreenVideo>
<keyboard>
<opensquarebracket>PlayerControl(tempoup)</opensquarebracket>
<closesquarebracket>PlayerControl(tempodown)</closesquarebracket>
</keyboard>
</FullscreenVideo>
</keymap>
The [ and ] keys don’t skip forward and back anymore but there is also no change of tempo.

I’m using Windows 10, Kodi 17 final build from 20170201. Are there more people having issues with this or am i doing something stupid? Is the playspeed anywhere shown? PlayerProcessInfo or PlayerDebug screen perhaps when enabled?