Hello. I made a small widget that adds a small red bar to the top of a view form, the code can be found in this imgur gallery: https://imgur.com/a/R5TfxpJ

When I try to install my module, Odoo throws me an error: 

Element '<xpath expr="//div[hasclass('o_form_sheet_bg')]">' cannot be located in parent view

Is it possible to display my widget without inheriting the stock.picking form view? I just want it to show up on top of it.