Sometimes you want to give a user the possibility to display the details of a column value with a lookup for this column. This works great when the columns have a value.
But when a column is not editable and not mandatory, the value could be empty. Take for example a table with transactions. The table is not editable and the columns production order and sales order are not mandatory. I want the users to be able to show detail information of the sales order and the production order. When they have a value the lookup works great. If a sales order has no value and I (accidentally) press the lookup, I get a complete list of all the sales orders. I think in this case it’s not necessary and it could take some time when it’s a large table to lookup.
I know it is possible to have a lookup table variant that shows a max number of records for a large table. But it could be easier by just hiding the lookup if the column is empty and not editable.
The gap between Always showing the action button and only When editable is indeed where your suggestion comes in. I like it!