v2.15.3
Menu: fix arrow navigation of SubMenu (#10304)
PopupManager: fix z-index cannot be rewritten at first using (#15738)
Loading: fix loading not disappear in some condition (#9313)
Accessibility for message & message-box & tabs (#7424)
Cascader: refactor and add multiple mode. (#15611)
clickoutside: fix memory leak
Calendar: add Calendar component (#14908)
DatePicker: support literal (#15525)
fix(utils.dom): fix utils.dom error (#21049)
Table/MessageBox/Tree: remove object-assign
Popper: fix memory leak on route change (#9757)
Chore: use resize-observer-polyfill to detect element resizes (#10779)
Utils: scroll-into-view should consider target element's offset parents (#11058)
ScrollBar: cache bar width calculation
Input / Select: fix Korean IME composition bug (#10648)
fix: update isFunction (#20912)
Image: Fix image ssr (#16737) (#16747)
Tooltip: displays when initial value is true (#14826)