I'm getting sick of posting this. This issue has been around forever, fix it already.

additionally, why does the minimap shrink half the time no matter the previous setting?

Bump... will get ignored but hey. This is an extremely annoying, ongoing issue that is really old.

Bump, has Riot at least acknowledged this is on their backburner?

Bumb, try using shift window to temp fix the problem...... I don't have this issue and I use multi gpu setup... It used to do it on ATI GFX but updated my drivers...

This happens to me too. I found a work-around for it though; it works for me at least. Try it.

1. Right-click the task bar and goto "properties".
2. Under "taskbar" tab, check "auto-hide the taskar" and click "apply".
3. Wait for the game to resize fully.
4. Check "auto-hide the taskar" again and click "ok"

HTH

Guys...

Click on the game
Alt+Enter

Then set it back to Windowed Borderless...