-Inventory changes. Now you cannot have more than one inventory open at a time, nor can you have one character operate on another's inventory via crafting.
Completely false. Opening up multiple inventories still works fine. So does operating on another's inventory (tested with repair hammer).
The only change I see is that when you switch active characters, your open inventory window(s) may change to a different character. Lots of people had asked for this, I guess. Hopefully they enjoy what they whined for, because it can be confusing as hell now when you switch active chars with multiple inventories open.
edit: I'm also going to guess that that last part is your source of confusion. To bring up additional inventory windows, right-click on character portraits, or left-click the inventory icon below their portrait.