Dialogs and Finder Windows Stretch to Full Height

Hi, I'm having an ongoing annoying problem.

Often when I go to Save a file, the dialog that opens to ask for name and location will be stretched to the full height of the screen. Not width, just height. Many times I have dragged the bottom of the dialog to make it smaller, but it never sticks. When I go to save again, the dialog is once again full screen height. This seems to happen in all kinds of different applications, not just a particular one. And it seems to always happen.

The same also happens with Finder windows if I have multiple tabs open. For example, the Finder window will be smaller when I bring it forward, but then as soon as I click on one of the tabs, it jumps to full screen height and does that for every tab open. As I've done with the Dialog box, I've resized the Finder window but it never sticks. While this problem always happens with dialog boxes, it's not as consistent with Finder windows. Sometimes when I click on a tab it doesn't change height, but sometimes it does. I have not been able to figure out what triggers it because it seems so random.

I've tried restarting my iMac and closing the Finder windows and then starting them back up. It never makes any difference, it seems like OS X is insistent on making dialogs and Finder windows full screen height for some reason.

I'm running El Capitan 10.11.1 on a late 2012 iMac 27". While this isn't a severe problem, it is incredibly annoying. Anyone else having this problem? Anyone know why this would be happening or having any suggestions for fixing it? Thanks.