That seems to work.  Here’s the pane after selecting an item:


When you press Equip, you see this:


The item is gone from the grid, and ‘unequip’ is an option.  Clicking that brings you back to the state shown in the picture at top.  I can tell that I’m going to need more information on this screen; specifically, the user needs more clues as to whether or not they want to swap out an existing piece of equipment for this one (without having to toggle back and forth to the char pane).  I’ll worry about that later on; for now, this gets Inventory to the basically functional state that I wanted it at.