src/vs/workbench/contrib/preferences/browser/settingsEditor2.ts/SettingsEditor2/updateChangedSetting
class SettingsEditor2:	private updateChangedSetting(key: string, value: any, manualReset: boolean, languageFilter: string | undefined): Promise<void> {
		// ConfigurationService displays the error if this fails.
		// Force a render afterwards because onDidConfigurationUpdate doesn't fire if the update doesn't result in an effective setting value change
		const settingsTarget = this.settingsTargetsWidget.settingsTarget;
		const resource = URI.isUri(settingsTarget) ? settingsTarget : undefined;
		const configurationTarget = <ConfigurationTarget>(resource ? ConfigurationTarget.WORKSPACE_FOLDER : settingsTarget);
		const overrides: IConfigurationUpdateOverrides = { resource, overrideIdentifiers: languageFilter ? [languageFilter] : undefined };

		const configurationTargetIsWorkspace = configurationTarget === ConfigurationTarget.WORKSPACE || configurationTarget === ConfigurationTarget.WORKSPACE_FOLDER;

		const userPassedInManualReset = configurationTargetIsWorkspace || !!languageFilter;
		const isManualReset = userPassedInManualReset ? manualReset : value === undefined;

		// If the user is changing the value back to the default, and we're not targeting a workspace scope, do a 'reset' instead
		const inspected = this.configurationService.inspect(key, overrides);
		if (!userPassedInManualReset && inspected.defaultValue === value) {
			value = undefined;
		}

		return this.configurationService.updateValue(key, value, overrides, configurationTarget)
			.then(() => {
				const query = this.searchWidget.getValue();
				if (query.includes(`@${MODIFIED_SETTING_TAG}`)) {
					// The user might have reset a setting.
					this.refreshTOCTree();
				}
				this.renderTree(key, isManualReset);
				const reportModifiedProps = {
					key,
					query,
					searchResults: this.searchResultModel && this.searchResultModel.getUniqueResults(),
					rawResults: this.searchResultModel && this.searchResultModel.getRawResults(),
					showConfiguredOnly: !!this.viewState.tagFilters && this.viewState.tagFilters.has(MODIFIED_SETTING_TAG),
					isReset: typeof value === 'undefined',
					settingsTarget: this.settingsTargetsWidget.settingsTarget as SettingsTarget
				};

				return this.reportModifiedSetting(reportModifiedProps);
			});
	}