This is located in the Appearance section of Interactive Grid Attributes in Page Designer. Once disabled, APEX will not automatically select the first row on page load any more.
After loading, the interactive grid page will look as follows - note that nothing is initially selected.
If all options, except the Search Field are disabled, the Interactive Grid page looks as follows:
Options which are turned off, are no longer visible in the Actions menu.
New declarative options are also available at the column level: we now can separately enable or disable the Sort option ( which was formerly a part of Sort / Control Break / Aggregate ). In addition to that, the ability of end users to hide a column can be turned off in Page Designer.
If the Control Break / Aggregate and Hide options are turned off, the column header menu looks as follows: