ossapha,
It has to do with the difference between the Window Marker (plan data) and the Window ID (schedule data):
1) To have have a unique plan text for every window in plan view:
In >Window Selection Settings, > Dimension Marker, > Customizing Texts, > Custom Text, input the info you want to see on the plan window marker.
These plan numbers will all be manually input by you...
2) For identical windows in the schedule, ie the "show uniform items as a single entry".
In >Window Selection Settings, >Listing and Labeling, > ID, input the ID that the schedule will use to list the windows.
When placing identical windows, turn off auto id increase, you'll have less manual inputting to do in the Listing and Labeling box.
Be very careful about using the eyedropper/Syringe, it will ruin your careful separation of ID vs marker.
This two step process will give you a single schedule entry for multiple identical windows, but every window will have a unique plan number.
My workflow is to get all windows placed with proper ID's, only then do I go through and renumber the Dimension Markers.
Snap