Course frame is really high on narrow LMS view

Hello,

Today I've noticed strange behavior on LMS - Moodle and SAP.

When the LMS window is narrow, the course published main#frame gets really high (see the screens). It strechs the whole window and course is centered inside of it. Roughly I can say, it can be up to 3x times the course height.

First, I thought maybe it is sidebar problem, because when I show menu, it goes all the way up and down that frame, when course is only 1/3. But I turned off sidebar and problem still existes. The "welcome" screen also goes really tall. 

Can I somehow prevent it (aparat of launching course in new window)? It seems quite like a bug.