title: drag and drop between mat-accordion
body: <p>I am trying to make drag and drop between mat-accordion. Problem is as long accordion is closed i am not able to drop any item to it.</p>
  
  <p>Here is my code</p>
  
  <pre><code>public groups: Array&lt;any&gt; = [
    {
      name: 'Group A',
      items: [{name: 'Item A'}, {name: 'Item B'}, {name: 'Item C'}, {name: 'Item D'}]
    },
    {
      name: 'Group B',
      items: [{name: 'Item 1'}, {name: 'Item 2'}, {name: 'Item 3'}, {name: 'Item 4'}]
    }
  ];
  </code></pre>
  
  <p>Html</p>
  
  <pre><code>&lt;mat-accordion&gt;
      &lt;mat-expansion-panel *ngFor='let group of groups'&gt;
        &lt;mat-expansion-panel-header&gt;
          {{group.name}}
        &lt;/mat-expansion-panel-header&gt;
        &lt;div *ngFor='let item of group.items' [dragula]='"first-bag"'&gt;
          &lt;div&gt;{{item.name}}&lt;/div&gt;
        &lt;/div&gt;
      &lt;/mat-expansion-panel&gt;
  &lt;/mat-accordion&gt;
  </code></pre>
  
  <p>Note: drag and drop is working fine if I drag and drop item to the same container but I want to be able to drop to closed accordion, line when I start drag accordion other accordion open and I can drop there.</p>