rols>
      </div>
      <div id="mainPanel" class="flex horizontal layout">
        <div id="ldrawer" class="drawer">
          <designer-tab class="single"><button>Components</button></designer-tab>
          <canvas-controls id="canvasControls"></canvas-controls>
          <tree-view name="tree" id="treeView"></tree-view>
        </div>
        <div id="mainView" class="flex vertical layout">
          <div class="horizontal layout" style="box-sizing: border-box;">
            <designer-tabs attr-for-sel