It's part of the design.
I don't think I explained myself properly. What I meant to say is that,
once you restore the Grid to its original non-maximized state, the Body still has fixed dimensions set (via CSS).
Thus, if you resize the window, the body remains the same
size (which now does not match its window), messing with the page design and any other content.
The feature seems potentially valuable for my user base so I'm testing a CSS workaround, it's just that this looks like a defect to me.