After you drag it to size, hold down the Control key, then go to File,
Close.
That should fix it.
Note this is only a semi-permanent fix. The next time your PC has a major
hiccup (such as when your screen flashes & a couple of items have
mysteriously disappeared from your Systray until you re-boot), you'll
probably find all your sizes have gone out the window (no pun) & will need
doing again.