No more to worry about how to play your favorite movies / videos into your TV...
And so you can stop the playback in any moment:
More handy and simple? impossible 
How? This option "Enviar a Chromecast" does not exist in my right-click menu regardless of the video format that I choose.
Frankly I woudn't know .... I don't use any smartTV functions on my Samsung. I simply connect them to a Raspberry Pi running Kodi, as I dislike "smart" features that stalk, patronize or tries to steal my privacy.. 
But maybe it might help to install chromecast functionality with "api mkchromecast" first. 
Are you using a recent version of Elive? I have the option in my thunar, maybe you can try:
~ ❯❯❯ apug
~ ❯❯❯ elive-skel upgrade .config/Thunar/uca.xml
