"Show times with miliseconds" option is greyed out

[jakobon]

It is amazing to see the "Show times with miliseconds" option available in the newest version, thanks !
I have just downloaded the SMPlayer Portable version 17.4.2, and under View -> OSD see the checkbox to enable the option, but it is greyed out and cannot be selected.
What are the requirements to get the "Show times with miliseconds" option enabled ?

[rvm]

You have to enable mpv as multimedia engine in preferences -> general.