I need to add line separator before my two newly created custom mass action "Custom Action 1" and "Custom Action 2" and
I got one of the resolution of my question. In order to add line separator between mass action just like Amasty extension. person should add this action in listing_massaction tag in ui component file. It belongs to sales order grid so ui component file should be sales_order_grid.xml
<action name="order_mass_separator"> <argument name="data" xsi:type="array"> <item name="config" xsi:type="array"> <item name="type" xsi:type="string">order_mass_separator</item> <item name="label" xsi:type="string" translate="true">----------------</item> </item> </argument> </action>
The only difference in this action with others that in this action there is no URL path define. So it is clickable but didn't do any thing.
One more important thing you can't skip item type
I hope my answer will help others as well. if anybody want to add line between custom mass actions in sales order grid, though I am not sure but there may be other solutions as well.