Easier way to set the view height

[brrd]

Is your feature request related to a problem? Please describe. See issue and workaround: #173

Describe the solution you'd like

.etabs {
  height: 100%;
}

.views {
  height: calc(100% - 33px);
}

Then we would be able to do :

<div style="position: relative; height: 300px;">
  <tab-group new-tab-button="true" sortable="true">
  </tab-group>
</div>
<div class="footer">Footer</div>