Missing UI elements when using a custom context

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.3.X, Master
• Fix Version/s: 7.3.10.3 DXP SP3, 7.3.X, 7.4.2 CE GA3, 7.4.13 DXP GA1, Master
• Component/s: CKEditor
• Labels:
  • ee-ts
  • liferay-dxp-73-sp3
• Branch Version/s:
  7.3.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Git Pull Request: https://github.com/liferay-frontend/liferay-portal/pull/1234

Steps to reproduce:

1. Set a custom context for the portal (e.g. /myportal). (https://help.liferay.com/hc/en-us/articles/360031260592--Change-root-context-to-custom-context)
2. Start the portal.
3. Create a web content.

 Actual behavior:
When the editor page opens, there is the following error message in the browser console regarding editor.css:

 On master I had to change the following property in tomcat/conf/catalina.properties (change ROOT to myportal in the path), as the location of the support-tomcat.jar changed and it's path has ROOT hardcoded in it, and it caused errors when I tried to start the portal with a custom context:

common.loader="${catalina.home}/webapps/myportal/WEB-INF/lib/support-tomcat.jar"...