Extra Background Space at Bottom of mixer.

So I just recently upgraded to Cubase 9 and at first all windows were fine, but then I started noticing the mixer window had some extra space. Over a few weeks the space has gotten bigger. I don’t know if I accidentally changed some setting, but this feels like a bug, is there any way to fix this?

Did you make and activate a workspace maybe?

Look on Workspace menu - if some letter beside “Workspace”.
You can make things look pretty much as you want.

Activate No Workspace and it all fills up screen for me.