You must search this line in the "sale.order.form" view and add the "limit" attribute with the number of lines you want to display.
<tree string="Sales Order Lines" editable="bottom" decoration-info="(not display_type and invoice_status == 'to invoice')" limit="100">
Needless to say, it is better to inherit the view and make changes to the inherited view.
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Another thing that the users can do is to click on the number of rows in the top of the list and change the range of rows to display. Users have to repeat this action every time they need it.
Hi, am using Odoo CE 12, seems like 40 is the default number of lines to be shown in one2many tree view. I'm glad if anyone could answer
This question is not well formulated, because reading it, it seems that you want to increase the number of lines in a sales order.