title: Customizing floating action button
body: <p>I am using sliver list and I want to use both floating action button and sliding_up_panel from pub with the following behaviour: when I scroll down my list, the floating action button disappears; when I scroll up the fab appears. Moreover, the fab should disappear when I slide up (open) the menu.</p>
  
  <p><a href="https://i.stack.imgur.com/Tb3Ow.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Tb3Ow.png" alt="enter image description here"></a></p>
  
  <p>As you can see above, the floating action button is all on the sliding element, but I want it to be between the sliding element and the scrolling item list.</p>
  
  <p><a href="https://i.stack.imgur.com/zQelp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zQelp.png" alt="enter image description here"></a></p>
  
  <p>Also in above picture, the problem is that the floating button is actually visible but I want to hide it with a nice animation when I slide up the sliding menu.</p>
  
  <p>I hope my question is clear!!!</p>