<div class="header">
    <div id="menu">menu</div>
    <div id="search"></div>
    <div id="tab">tab</div>
</div>

#header {
  position: relative;
}

#menu {
  position: absolute;
  bottom: 0;
  top: 0;
  width: 20%;
  right: 80%;
  background: green;
}

#tab {
  position: absolute;
  overflow: auto;
  right: 0;
  z-index: 10;
  padding: 1.2rem;
  left: 20%;
  background: red;
}