Function enableHover

src/components/modebar/manage.js:221–228

(a)

    var enabledHoverGroup = [];
    var enableHover = function(a) {
        // return if already added
        if(enabledHoverGroup.indexOf(a) !== -1) return;
        // should be in hoverGroup
        if(hoverGroup.indexOf(a) !== -1) {
            enabledHoverGroup.push(a);
        }
    };
    if(Array.isArray(buttonsToAdd)) {
        var newList = [];
        for(var i = 0; i < buttonsToAdd.length; i++) {