4.22.0

• Add the Workspace startExternalDrag method, which drags a new tab in from outside of the workspace (e.g. from a palette of widgets). - #808
• Add the Workspace acceptExternalDrop prop, which creates tabs from the browser's drag and drop (e.g. draggable elements or files). - #808
• Add the useTabListOverflow hook, which returns the ids of a tabset's tabs that are scrolled out of view (e.g. for an overflow menu), and the getTabListOverflow and subscribeToTabListOverflow methods. - #816
• A selected Workspace tab is scrolled into view if its tab list overflows, and useParentTabset has a new selectTab method. - #816
• Add the usePopoutWindows hook, which opens Workspace tabs in popup windows (e.g. from a "pop out" button), copying the page's styles, and docks them back when the windows are closed. - #821
• Deprecate the Workspace onTearOff prop (and TearOffArgs and the drag preview's isTearOff): browsers don't reliably report where a drag outside of the window ends, and some block popups opened then. Open popout windows from a button instead; it will be removed in the next major version. - #826
• Add the Workspace copyTab and copyTabset props: tabs (and tabsets) dropped while Option (macOS) or Ctrl is held are copied rather than moved, and reported with the new "copy" reason. - #809