Not sure if there is more to your question but on the surface.
Drop downs are not created within schedules. they are simply a type of property created by the property Manager. The drop down options are created within the property manager together with a default. When the property created is selected in a schedule, assuming it is attached to the object, it is brought in as a drop down together with all of the options or the default. The drop down option can then be selected either in the schedule or the object.
Watch these 4 short clips on YouTube (about 10 minutes overall). They talk about the various Data Types that ARCHICAD Element Properties can have. As you know, these Properties appeared in AC20, and they can be listed in Schedule Fields.
If you specify that a Property's Data Type is "Option Set", you can define that Option Set in the Property Manager and when that Property is scheduled, that set of options will appear in the Schedule as a drop-down list, and you can select any of the options from the list to modify the Property's value.
If you specify that a Property's Data Type is "True/False", when that Property is scheduled, you will see a checkbox appear in the Schedule and you can check or uncheck the checkbox to represent a True (or YES or 1 or ON) or False (or NO or 0 or OFF) value or state.
The information really helps explain the functionality and I hope to utilize this:)
I wonder, will this information transfer over in IFC or will there need to be some special configuration here? I'm a bit curious as it seems that both this, IFC, and attributes section could be merged into one area.
One more question regarding schedules: I've been interested in collapsing my door and window schedules to show the individual instances of each element. I've also needed to keep the room/zone name and number to be able to locate these elements efficiently, so just about every instance of an element is an individual entry in the schedule.
I would rather not have a manual work around to list all these locations in one cell, so I've been pondering if there is a way to collect this automatically, and can't find a way to do so.
With the location, room and number, there seems to have been a workaround changing parameters in the GDL, but that seems to no longer work:
With regards to how one does this, I thought there might be a way to use Tags from the Property Manager to do this, but I would still need to have that info called from somewhere and would be redundant to using the properties that list that information. But then there seems to be no way that multiple instances of some information can be collected together anyway. So then what ? The Sum functions in the schedule can only be used for column numbers/integers throughout a column, but not for text in one cell... ?