Multiple Custom Data Fields in different profiles

u mean as one MULTISPORT activity or otherwise?

If otherwise - it should be doable. I am currently doing it.

Yup. Tested. Can have.
2 for each activity profile.
2 - run
2 - indoor run

MULTISPORT. No idea.

just tested MULTISPORT - dualthlon mode

It's using the existing configured sports profile. Hence, - no issue as well.

Maybe I misunderstand/missed what you are trying to do.

I found the error

I had to generate the templates from scratch and then copy in the new code.

Since the data fields all had the same structure, I had copied the projects and edited the files to reflect the new functionality, names, and classes. Turns out there is a key somewhere (perhaps the application.id field in the manifest.xml file?) that the devices uses to load/index them - NOT THE NAME. Thus, when I downloaded them, it overwrote the old ones. Since my custom data fields have two basic displays, I started with two separate working data fields. When I downloaded the new swim data fields, would overwrite the run data fields and vice versa.

Thanks NIKEOW, I've got it solved now.

I had to generate the templates from scratch and then copy in the new code.

Since the data fields all had the same structure, I had copied the projects and edited the files to reflect the new functionality, names, and classes. Turns out there is a key somewhere (perhaps the application.id field in the manifest.xml file?) that the devices uses to load/index them - NOT THE NAME. Thus, when I downloaded them, it overwrote the old ones. Since my custom data fields have two basic displays, I started with two separate working data fields. When I downloaded the new swim data fields, would overwrite the run data fields and vice versa.

Thanks NIKEOW, I've got it solved now.

Things which needs changing
Resources.xml (the app name)
Manifest.xml - the unique Id

Else one will overwrite the other or even delete all other apps /PRG in your apps folder.

With CIQ, there is the concept of "slots" on the device. You see this info under "manage storage" for the device on GCM. On the VA for example, there are 16 "slots", meaning you can only have 16 CIQ "things" installed.

I thought I read somewhere that these slots are subdivided, and you can have up to "a" watchfaces, "b" widgets, "c" apps, and "d" datafields on the device, and a+b+c+d<=16.

Could it be the slots on the device for datafield has hit it's limit? Of maybe just you've used all 16 slots (if there is no subdivision)?

With CIQ, there is the concept of "slots" on the device. You see this info under "manage storage" for the device on GCM. On the VA for example, there are 16 "slots", meaning you can only have 16 CIQ "things" installed.

I thought I read somewhere that these slots are subdivided, and you can have up to "a" watchfaces, "b" widgets, "c" apps, and "d" datafields on the device, and a+b+c+d<=16.

Could it be the slots on the device for datafield has hit it's limit? Of maybe just you've used all 16 slots (if there is no subdivision)?

I think, but I don't have the documentation to provide it, that the auto-generated id key is required to be unique. If two slots items have the same key, they will overwrite each other. Thus, to develop derived elements, you have to have the template generated vice using the Eclipse copy/paste project. When I generated new templates, I was able to get multiple fields on the 920xt.

Thanks for the insight on the max number of slots. I'm always amazed at Garmin's use of seemingly random limits.