Oh my goodness, this can be an annoying issue with iTunes.
The problem is: iTunes will restore itself or maximize itself all the time every 20 or so seconds without being clicked on, it will also get main focus and whatever you were doing will have to wait!
I solved this by right clicking on the iTunes program icon where I launch it from and selecting Properties, then selecting “Compatibility” then making sure “Run this program as an administrator” was checked.
When first starting iTunes I now have to click on “Yes, I would like to start this program as an administrator….blablabla…” but it’s a LOT less irritating than having to constantly minimise iTunes.