Can't choke out enemies when I am right literally behind them as they're sitting

[Oedipus's Stepdad]

The options are just greyed out. is is makes stealth very ♥♥♥♥♥♥♥ annoying

[HunZolka]

When there is something that would get in your way or you're somewhat to the side of him instead of right behind it is disabled.

Same when he's not on the same level as you (walking up/down stairs)

[Vanzann]

Happens sometimes, with guys leaning against the wall too. Try distract them with stones, they should move and make stealth kill possible.