Major In my case, I call the cms url with ?uitool=uitool-sitemap
If the sitemap tool is already opened, there is a js error.
TypeError: Cannot read property 'isVisible' of null TypeError: Cannot read property 'isVisible' of null at constructor.onChildNodesAvailable (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:117928:40) at Object.callback (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:9249:30) at constructor.onChildNodesAvailable (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:119591:25) at Object.callback (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:9249:30) at constructor.onProxyLoad (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:120589:9) at constructor.triggerCallbacks (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:88021:13) at constructor.setCompleted (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:87988:9) at constructor.setSuccessful (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:88002:13) at constructor.process (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:87900:13) at constructor.processResponse (http://localhost:8220/cms/plugins/extjs6/resources/ext-all.js:97681:13)