I'm wondering if it's possible to create functionality like windows file explorer tree has, or web page dropdown with multiple sub menus? Or just to simulate the flow. 

I need it for category selection for tickets so it has to be usable as selection in form view. It has to be built from a single database model where all records are stored and you build the sub categories with recursion function that checks if the record has a parent. Relations One2many won't work because there need to be at least 4 levels so that is why it needs to be in a single DB table. 

Has any one seen anything that would at least simulate such behavior. So when you select an item that has children it shows the children in it doesn't it selects it. Don't even know what to google because every time I use tree it shows me only things odoo "Tree" list view.