Comment Current-line: Ctrl + k        (uncomment: Ctrl + shift + k).
Move Current line up(without selection):Ctrl+shift+Up arrow
Move Current line down(without selection):Ctrl+shift+Down arrow
Ctrl+(+): Zoom in
Ctrl+(-): Zoom out
Mark particular line: click on the empty space between line number and gray/whhite boundary.
Ctrl+Shift+Alt+R: Open in Chrome (default open in chrome browser).

All shortcuts: Keyboard And Mouse Shortcuts