* have explicit methods for changing the scroll position (delayed/smooth vs now/direct) that bubble up to the editor internals.
* have all other clients of ScrollableElement not use smooth scrolling

Workbench theme customisation for forground tab colour of inactive group appears to be missing (fixes #27067)

Closing a tab using middle mouse button on the 'x' causes the tab to the right to also be clsosed (fixes #25529)

themes - get rid of tab.activeWithInactiveEditorGroupForeground and inactiveWithInactiveEditorGroupForeground

fixes #21762