Hi Michael,

please check this eg:

if button is defined like this:

<button name="action_confirm" states="draft" string="Confirm Sale" type="object" context="{'show_sale': True}"/>

Replace it like:

<xpath expr="//button[@name='action_confirm']" position="replace">

    <button name="action_confirm" states="draft,pending" string="Confirm Sale" type="object" context="{'show_sale': True}"/>

</xpath>

 When states property is added to a button, you cannot use invisible or attrs to control the visibility, because it simply doesn't work, instead try to add convenient property i.e either stick to states or go with attrs, but not both to a button. 

So if want to change the states, then  try this below one

<xpath expr="//button[@name='action_confirm']" position="attributes"> 
     <attribute name="states">pending</attribute> 
</xpath>