in grid customize dialog, clear all field in selected list and click ok make this customize is deleted.
same as IDEMPIERE-2718, i think it's work-around solution for delete a grid customize.
maybe change as below:
+ if selected list is clear, disable ok button.
+ add a reset button in top of selected list (near up/down).
if user click reset => reset list to default (no customize)
after that, if user click ok. display a confirm dialog "old customize will deleted"
, that behavior of deleting the customization when all fields are cleared is intentional - if I recall correctly some time ago suggested to implement a "Reset" button (don't remember if it was in forums or JIRA)
I agree a reset button can be less confusing for the user and the clear list is hidden, more like a workaround or hack.
This seems like a duplicate of