TypeError: element is null nprogress.js:463:5 occurs in back-end editor when first loading existing map

[alexboia]

Describe the bug When the back-end editor is opened for the first time and the Map tab is selected, if there is a GPX track already uploaded, after loading the map, the following error occurs in the browser console:

TypeError: element is null nprogress.js:463:5 classList http://alexboia.net.local:8080/wp-content/plugins/abp01-travel-tech-box/media/js/3rdParty/nprogress/nprogress.js?ver=0.2.0:463 removeClass http://alexboia.net.local:8080/wp-content/plugins/abp01-travel-tech-box/media/js/3rdParty/nprogress/nprogress.js?ver=0.2.0:444 remove http://alexboia.net.local:8080/wp-content/plugins/abp01-travel-tech-box/media/js/3rdParty/nprogress/nprogress.js?ver=0.2.0:257 set http://alexboia.net.local:8080/wp-content/plugins/abp01-travel-tech-box/media/js/3rdParty/nprogress/nprogress.js?ver=0.2.0:98

To Reproduce Steps to reproduce the behavior:

1. Go to Go to 'Edit trip summary' -> 'Map' after having uploaded a GPX track and fully reloaded the page afterwards.
2. Open the browser console (Firefox);
3. Click on 'Map'.
4. Wait for the GPX track to be loaded
5. See error in the console

Expected behavior No error should be generated in the console.

Desktop (please complete the following information):

• Browser Firefox
• Version 74