Recently I answered a question about where to change the number of displayed records of a Popup LOV in Oracle APEX and I thought it could be of general interest.
The behavior of Popup LOVs can be changed through the Popup Lov template. You can find it at
Shared Components\Templates\Popup LOV.
In the Pagination section you will find the property Display which defines how many records are displayed at once.
The Popup LOV template also contains other interesting settings like the icon which is used for the popup lov field or the text for the search button, the width and height which is used to display the popup lov window and much more. Just have a look!