Image disappearing from Fitbit full screen event

[cramis1]

I have an image element that keeps disappearing whenever the watchface has a full screen event, like when it receives a call and the call overlays the watchface. When the call notification ends, the image is no longer displayed and the watchface has to be restarted. This also sometimes happens when the charging screen is displayed.

The image is a DOM element that selects between one of a number of .png files based on a received condition. The DOM works perfectly well all other times, it just disappears on a full screen event.

The DOM is defined in the index.gui as

<image class="SVGobjects" id="arrow" href="icons/even.png" visibility="visible" />

And the properties are changed in the index.js as

const arrow = document.getElementById("arrow");
...
if(delta === "FortyFiveUp" ) {
    arrow.href = "icons/up.png";

  }
  else if(delta === "SingleUp" ) {
   arrow.href = "icons/singleUp.png";

  }
  else if(delta === "DoubleUp" ) {
    arrow.href = "icons/doubleUp.png";
 
  }
  else if(delta === "FortyFiveDown" ) {
    arrow.href = "icons/down.png";

  }
  else if(delta === "SingleDown" ) {
   arrow.href = "icons/singleDown.png";

  }
  else if(delta === "DoubleDown") {
    arrow.href = "icons/doubleDown.png";
  } else if (delta === "Even") {
    arrow.href = "icons/even.png";
  } else {
    arrow.href = "icons/even.png"; 
  }

Any ideas? Not sure how to fix this as there is nothing the watchface can see as to whether a full screen event occurred.