title: Entire view FPS drop when GMSMarker tracksViewChanges set to true
body: <p>In Google Maps SDK for iOS, <code>tracksViewChanges</code> of <code>GMSMarker</code>, when set to <code>true</code>, likely caps FPS for other views in the entire view controller.</p>
  
  <p>Some facts to start with:</p>
  
  <ul>
  <li>VC has a map with 5 <code>GMSMarkers</code>, and one collectionview with corresponding 5 cells</li>
  <li>Markers have custom iconView</li>
  <li>When scrolling collection view, cells in this collection AND markers are supposed to dynamically update their appearance (progressive animation directly tied to scroll event)</li>
  </ul>
  
  <p>The scrolling animation, however, is choppy and anything but 60 FPS smooth. </p>
  
  <p>You might say that's a performance reason but it's not the case, see:</p>
  
  <ul>
  <li>Xcode reports low memory usage and constant 60 FPS.</li>
  <li>Performance issues are 100% comparable on iPhone 5 through 7.</li>
  <li>When all views are removed (both from markers and collection view cells, having set only backgroundColor) and no animation methods are called, the scrolling still feels choppy, despite non-existent performance reasons for it.</li>
  <li>Same as with scroll, this affects some panning interactions as well, so its not exclusive to scrolling views.</li>
  </ul>
  
  <p>Basically when all markers have <code>tracksViewChanges</code> set to <code>false</code>, I achieve heavenly animations. Even if I fake markers with custom UIViews, the FPS doesn't drop <em>at all</em>, even on old devices.</p>
  
  <p>Now, if I set only ONE marker to have <code>tracksViewChanges</code> set to <code>true</code>, the FPS drop returns. Amount of markers that have enabled that parameter does not matter. I consider a FPS drop anything below 60 FPS, in this case, however, we're talking ~30 FPS.</p>
  
  <p>Does this ring a bell? </p>