Hide region when block menu is empty I got the 2nd level main menu in a block in the sidebar, drupal 8 correctly hides the menu (and the block) when the user browses a page that is not in this menu, but the theme continues to show the empty region. 
The condition {% if page.region %} is true. 
is there any way to solve this problem?
It is better to use construction

{% if page.region|render|striptags|trim|length &gt; 0 %} ... {% endif %}


So you can check if there is some content or not.