[Ace]

At the bottom of the screen a little button that says "Sellout" should appear when the window is closed. You click that to open it now. The button can be dragged side to side as well.

If you want to convert/desynth gear, you go into the Convert or Desynth tabs, in the Item tab, and pick the things...

Edit: I may know the reason, looking into it, I think a function I was expecting to be released by now was not added yet. I may have to internalize it for now and push a new release.