src/vs/workbench/browser/parts/notifications/notificationsViewer.ts/NotificationsListDelegate/computePreferredHeight
class NotificationsListDelegate:	private computePreferredHeight(notification: INotificationViewItem): number {

		// Prepare offset helper depending on toolbar actions count
		let actions = 1; // close
		if (notification.canCollapse) {
			actions++; // expand/collapse
		}
		if (isNonEmptyArray(notification.actions && notification.actions.secondary)) {
			actions++; // secondary actions
		}
		this.offsetHelper.style.width = `${450 /* notifications container width */ - (10 /* padding */ + 26 /* severity icon */ + (actions * (24 + 8)) /* 24px (+8px padding) per action */ - 4 /* 4px less padding for last action */)}px`;

		// Render message into offset helper
		const renderedMessage = NotificationMessageRenderer.render(notification.message);
		this.offsetHelper.appendChild(renderedMessage);

		// Compute height
		const preferredHeight = Math.max(this.offsetHelper.offsetHeight, this.offsetHelper.scrollHeight);

		// Always clear offset helper after use
		clearNode(this.offsetHelper);

		return preferredHeight;
	}