ohif-viewer/Packages/viewerbase/client/components/viewer/simpleToolbarButton/simpleToolbarButton.html

<template name="simpleToolbarButton">
    <button id="{{id}}"
    		type="button"
    		class="{{classes}} btn btn-sm {{activeClass}}"
    		data-container="body"
    		data-toggle="tooltip"
    		data-placement="bottom"
    		title="{{title}}">
        <span class="{{iconClasses}}"></span>
    </button>
</template>