Keep controls visible while scrubbing on mobile

[theazgra]

Hi,

currently while scrubbing on mobile, the controls with timeline dissappear. This is rather strange to us.

Would it be possible to add option to keep controls visible while scrubbing?

I have originally opened bug report in Mux Player repository: muxinc/elements#714

[jakubslambor]

+1

[luwes]

Closing discussion in favor of #751