Web Widget One2many Tree Line Duplicate

This module adds an optional "Duplicate Line Button" column to list views. It is available when the list is an embedded one2many list that allows creating records and the field is configured with the allow_clone option.

• A clone icon appears on each line; clicking it copies that line and inserts the copy right after the original.
• Section, subsection and note lines are not duplicable, so no clone icon is shown for them.
• The copy keeps the original values exactly, including computed values such as subtotals, and also copies the sub-lines of any nested one2many fields, recursively.
• Values that Odoo would normally recalculate when creating a line (for example a price coming from a product) are preserved as they were on the source line.
• Users can show or hide the clone column from the optional columns dropdown; the choice is remembered in the browser.

It works purely in the web client and does not add menus, reports, server models or scheduled actions. It only changes how list views behave, so it can be used on any editable list, such as order lines or invoice lines.