How do I stop my inventory from expanding every time I move something?

[Annalise Ember]

It's extremely annoying when I am trying to keep my inv. organized and every time I move something, every single folder opens. Then I have to close them all before I can move anything else.

I looked through debug settings to see if there was something in there but didn't see anything.

[Rolig Loon]

I'm not sure exactly what you are seeing.  Any folder will open to show you everything that is in it if you hold your cursor over the folder long enough.  "Long enough" defaults to one second, but you can increase that time as much as you like by changing the value in the debug setting InventoryOpenAutoDelay.   If you are using Firestorm or some of the other TPV's you also have a button at the top of inventory that will collapse ALL folders.  That can be handy of you have several folders open and are getting lost.

[Ohjiro Watanabe]

I know, it just makes me want to jump up and down sometimes. You could try Firestorm Viewer. The inventory is a bit better behaved and it has a Collapse button that shuts every folder.