The Item Editor window has a "Refresh Preview" button under Graphics->GFX. How do I make the preview stale and in need of a refresh?
So, that "Refresh Preview" button...
That button is created by ItemEditorDialog::view() in itemeditor.cpp
To make the preview stale, first select an item that's animated in the Select Item window and click 'Edit' - for example a fairy. Then trying changing the animation speed in that GFX tab.