@sasha573 Hi, sorry for delay, a quick update - the this.stores[0] exception has been fixed and should be integrated in the main codebase soon, please track the status here: https://github.com/bryntum/support/issues/5718.
I'll be looking at the UI refresh now, please track it here: https://github.com/bryntum/support/issues/5394
Both fixes should be there in 5.2.6
