Editor: ExtJS-Cache and DOM are not the same

Problem: *)

• open lectoring task
• open segment
• triple click to copy source
• place cursor in target and use CTRL+V
• Error is: "Uncaught Error: DOM element with id ext-element-40 in Element cache is not the same as element in the DOM. Make sure to clean up Element instances using destroy()"

*) This in example only; this has also been observed in other situations, but none of them was reliably reproducable so far. Might only happen after reloads and opening the same segment then. And seems to occur only with SpellCheck-Plugin activated.