title: MixItUp: An operation was requested but the MixItUp instance was busy
body: <p>I have currently some crazy trouble with MixItUp 3.</p>
  
  <p>I'm using the same Script and functions on the home page and also the subpages.</p>
  
  <p>But only on home there will be a warning after the first filter process "WARNING: An operation was requested but the MixItUp instance was busy. The operation was rejected because the queue is full or queuing is disabled.".</p>
  
  <p>The same script is also on subpages with the same data, but there it works fine.</p>
  
  <p>Website: <a href="https://www.busse-miessen.de/relaunch-2018/#anwaelte" rel="nofollow noreferrer">https://www.busse-miessen.de/relaunch-2018/#anwaelte</a></p>
  
  <p>Script: <a href="https://www.busse-miessen.de/relaunch-2018/wp-content/themes/busse-miessen/js/main.js" rel="nofollow noreferrer">https://www.busse-miessen.de/relaunch-2018/wp-content/themes/busse-miessen/js/main.js</a></p>
  
  <p>Here you can find the most important part of the script:</p>
  
  <pre><code>var containerEl = document.querySelector('.media_list');
  var mixer = mixitup(containerEl);
  
  jQuery('#cat-expertise, #cat-rechtsgebiete').on('selectric-change change', function(e){
  
      if( mixer.isMixing() ) {
          console.log('isMixing: ' + mixer.isMixing());
          //return;
      }
  
      var $val = jQuery('#cat-expertise').val();
      var $val2 = jQuery('#cat-rechtsgebiete').val();
  
      console.log('$val: '+ $val +' - - '+'$val2: '+ $val2);
  
      var $filter = false;
  
      if( $val != '0' ) {
          //console.log($val);
          $filter = '.'+$val;
      }
  
      if( $val2 != '0' &amp;&amp; $val != '0' ) {
          //console.log($val2);
          $filter = $filter+', '+'.'+$val2;
      } else if( $val2 != '0' ) {
          $filter = '.'+$val2;
      }
  
      console.log('final filter: '+$filter+' - State: '+mixer.isMixing());
  
      if( $filter ) {
          mixer.filter($filter);
      } else {
  
          $filter = '.mix';
  
          mixer.filter($filter);
      }
  });
  
  jQuery('#mix-sorting').on('selectric-change change', function(e){
  
      if( mixer.isMixing() ) {
          console.log('isMixing: ' + mixer.isMixing());
          //return;
      }
  
      var $val = jQuery('#mix-sorting').val();
  
      mixer.sort('name:'+$val);
  });
  </code></pre>
  
  <p>It seems that "mixer.filter($filter);" (main.js #120) could not be finished, because after the first call of filter() the isMixing() function is all the way "true" also after MixItUp has completed.</p>
  
  <p>Example output of the console.log() from above:</p>
  
  <pre><code>main.js:101 $val: cat-bauen-und-immobilien - - $val2: 0
  main.js:117 final filter: .cat-bauen-und-immobilien - State: false
  main.js:94 isMixing: true
  main.js:101 $val: cat-bauen-und-immobilien - - $val2: 0
  main.js:117 final filter: .cat-bauen-und-immobilien - State: true
  main.js:94 isMixing: true
  main.js:101 $val: cat-healthcare - - $val2: 0
  main.js:117 final filter: .cat-healthcare - State: true
  main.js:94 isMixing: true
  main.js:101 $val: cat-healthcare - - $val2: 0
  main.js:117 final filter: .cat-healthcare - State: true
  main.js:94 isMixing: true
  main.js:101 $val: cat-familie - - $val2: 0
  main.js:117 final filter: .cat-familie - State: true
  plugins.js:48 [MixItUp] WARNING: An operation was requested but the MixItUp instance was busy. The operation was rejected because the queue is full or queuing is disabled.
  </code></pre>
  
  <p>Please note, that this part is currently only commented out for debugging:</p>
  
  <pre><code>if( mixer.isMixing() ) {
      console.log('isMixing: ' + mixer.isMixing());
      //return;
  }
  </code></pre>
  
  <p>If I use it with the «return» there, the script stops also working, because "mixer.isMixing()" is true all the time after the first call of filter().</p>