problem:

• Open a task for editing.
• Reload the page with the opened task (with emptying the cache).
• Now open a segment for editing.
• Result is:
  ext-all-debug.js:194368 Uncaught TypeError: Cannot read property 'match' of null
  at constructor.syncValue (ext-all-debug.js:194368)
  at constructor.getValue (ext-all-debug.js:194397)
  at constructor.checkChange (ext-all-debug.js:169403)
  at constructor.setValue (ext-all-debug.js:169291)
  at constructor.setValue (ext-all-debug.js:194327)
  at constructor.setValueAndMarkup (HtmlEditor.js?_dc=1553004630165:200)
  at constructor.loadRecord (RowEditorColumnParts.js?_dc=1553004629953:315)
  at constructor.startEdit (RowEditor.js?_dc=1553004629916:378)
  at constructor.callParent (ext-all-debug.js:12493)
  at constructor.startEdit (RowEditorColumnParts.js?_dc=1553004629953:272)

This does NOT happen if there is no LanguageResource assigned to the task.

This might not cause too much trouble for end users. But I was trying to fix a bug, and this error obfuscates very much the problem that I was working on.