Invisible Last Post column from sub-forum

[jenda3]

Hi,

i have a little problem. I can't see last post from sub forum in Last Post column in main page.

I have this forum tree
Attachment 156918

and when i write something to level 4 then Last Post column in main page is empty. But show me user name and time of post.
Attachment 156919

But when i write something to level 3 then Last Post column in main page show last post from level 3
Attachment 156920

Is there any way to make the last post from level 4 visible in main page?

Thanks!