https://github.com/sencha/ext-web-components/blob/a107759b506996683fdf93654d6d641389ff2c4c/packages/ext-web-components-classic/src/common/webcomponentsbase.js#L416 i found this bug, fix need change "isClassicDock(childxtype)" to "isClassicDock(childCmp)"
ext-web-components/packages/ext-web-components-classic/src/common/webcomponentsbase.js
Line 416 in a107759
i found this bug, fix need change "isClassicDock(childxtype)" to "isClassicDock(childCmp)"