<!-- my context menu -->
<ul class="context-menu"
    ref="contextMenuTrack"
    v-if="openedMenu === 'contextMenuTrack'"
    v-bind:style="{top: top, left: left}"
    v-on:blur="closeMenu()">
    <li v-on:click="removeTrack(project.structure.tracks.indexOf(targetOfMenu));closeMenu()">delete track</li>
</ul>
<div>

    [ ...... stuff here ......]

    <!-- Where the menu is called-->
    <li class="track"
         v-for="track in project.structure.tracks">
        <div class="track-name-row">
            <li @contextmenu.prevent="openContextMenuTrack(track,$event)"
                v-on:click="expandTrack(project.structure.tracks.indexOf(track))"
                class="track-color-viewer"></li>

                [ .... other li tags .....]
        </div>
    </li>

    [ ...... stuff here ......]

</div>

data() {
    return {
        //the kind of menu which is opened
        openedMenu: undefined,
        //the coordinate of the menu
        top: "0px",
        left: "0px",
        //the element which is targeted by the menu
        targetOfMenu: undefined
    };
},

methods: {

    setMenu(top, left) {
        this.top = top - 170 + "px";
        this.left = left + "px";
    },

    // opening menu : calling set menu whith x and y
    openContextMenuTrack(track, event) {
        this.openedMenu = "contextMenuTrack";
        this.targetOfMenu = track;

        this.$nextTick((() => {
            this.$refs.contextMenuTrack.focus();
            this.setMenu(event.y, event.x);
        }).bind(this));
    },

    closeMenu() {
        this.openedMenu = undefined;
        this.targetOfMenu = undefined;
    }
}