how hide firefox (and other applications) titlebar in kde

how can i hide firefox titlebar to maximise screen space in kde?

with right click on titlebar and then >advanced>no border i can hide this not useful feature but window bottons (close, maximise, minimise) disappier in this method.

in MS windows there is not any titlebar for firefox and therefor screen size is bigger and more beautiful, also ubuntu in unity solved this problem with global taskbar.

Try pressing

F11

i solved this myself.

**1- **install following them for firefox:
https://addons.mozilla.org/en-US/firefox/addon/oxygen-kde/?src=ss

**2- **do guidances of following site:
chrome://oxygenkdeoptions/content/page/exceptionsguide.html

done, enjoy!