Drupal Juicebox Caption dropdown has only two options

I struggled to duplicate this but finally ...

I think that captions, for the most part are determined by the xml file that is associated with a given album. These files have a section that looks like this:

<juiceboxgallery 

	useLargeImages="true"
	resizeOnImport="false"
	importTitle="NONE"
	importCaption="IPTC"
	enableAutoPlay="true"
	autoPlayOnLoad="true"
	captionPosition="BELOW_IMAGE"
	captionHAlign="CENTER"
	showImageNumber="false"

I believe the Juicebox javascript program uses this section of code from the xml file. Of course the Javascript is not open source so who knows?

I did find one old and unused content type on my system that reflects what you are looking for. There is an image field in it. It has the field name "jb_image" and the field type image. In the Manage Display screen for that content type it has the format set for Juicebox Gallery and that enables a long drop down area that includes:

Image style: Juicebox small (800x800)
Thumbnail style: Gallery Thumbnail
Caption source: Image - Alt text (processed by fallback text format)
Title source: Image - Title text (processed by fallback text format)
Additional Juicebox library configuration options may also be set.

In other words I think that if you have an image field with the format set to Juicebox Gallery it may do what you want.

I suspect that using the xml file when building the gallery may be more effective. 10 years ago when Juicebox was written and worked in conjunction with Juicebox Builder Pro things worked pretty reliably. Over the years, not so much.

I'm looking (and spending all my time) on the Solo Theme in conjunction with Paragraphs and some Views and Javacript based gallery generators that depend on paragraphs.

and I see that we've overlapped our time frames with responses. Sorry.
Are you using the xml files to drive your galleries at all?