1.4.0: element has border-bottom: 2px, tether fails to include it in translateY height calculation

[lkraav]

It's a stack of 3 bars at the top of the viewport.

HEIGHTS

• adminbar: 32px
• target: 55px
• element

BAD TETHER RESULT
transform: translateX(0px) translateY(85px) translateZ(0px)

CORRECT RESULT
transform: translateX(0px) translateY(87px) translateZ(0px)

Is this a Tether bug or a general box model issue I'm missing?

var options = {
    element: "#menu-subsidiary",
    target: getTetherTarget(),
    attachment: "top left",
    targetAttachment: "bottom left",
    targetModifier: "visible",
    constraints: [{
        to: "window",
        pin: true
    }],
    optimizations: {
        gpu: true
    }
};

var tetherMenuSubsidiary = new Tether( options );