src/vs/workbench/browser/parts/editor/editorActions.ts/AbstractSplitEditorAction/registerListeners
class AbstractSplitEditorAction:	private registerListeners(): void {
		this.toDispose.add(this.configurationService.onDidChangeConfiguration(e => {
			if (e.affectsConfiguration('workbench.editor.openSideBySideDirection')) {
				this.direction = preferredSideBySideGroupDirection(this.configurationService);
			}
		}));
	}