Tab Stacking

Not sure if this has been asked before, but are there any plans for having tab stacking a part of zen (much a like to how it is on vivaldi) I instinctively try to stack tabs when in zen and then realize a second later why it isn't working (probably because the ui are somewhat similar and the side tabs reminds me of vivaldi) I use mainly use firefox (and now zen), but also vivaldi sometimes mainly for this feature (also a few others but I don't expect zen to be a 1:1 copy of vivaldi)