src/vs/workbench/browser/parts/editor/editorGroupView.ts/EditorGroupView/copyEditor
class EditorGroupView:	copyEditor(editor: EditorInput, target: EditorGroupView, options?: IEditorOptions, internalOptions?: IInternalEditorTitleControlOptions): void {

		// Move within same group because we do not support to show the same editor
		// multiple times in the same group
		if (this === target) {
			this.doMoveEditorInsideGroup(editor, options);
		}

		// Copy across groups
		else {
			this.doMoveOrCopyEditorAcrossGroups(editor, target, options, { ...internalOptions, keepCopy: true });
		}
	}