To go back to the basic, I created a very simple workflow:
1 input with type VC:VirtualMachine
Nothing else.
When I then click "Run", the VM browser appears and I can select a VM.
Just as simple and as expected.
Then I make it available in the catalog.
When I select "Request" and to to the VM selector, it keeps searching without any result.
See image for the steps and the empty result at the end.
(When selecting "Run" in the very first step, I do get the VM selector!)
vRO log simply says nothing.
Can confirm we see the same as you when exposing vRO workflow via Service Broker catalog.
Appears that this is just the "Tree Picker" from vRO not working as expected. If you change it to the standard "Value Picker" then you can get the VMs searched and returned as you start typing in the input.
Took a quick look in the logs and did not see anything obvious either.
I'm uncertain if Tree Picker is supported in SB Forms, as if you try to edit the custom form in SB for this workflow, you only get option of "Value Picker"
May not be ideal in your case, but it will work.
I don't think it'll work, only value picker mentioned in the docs:
When I created it, I created an input of type "VC"VirtualMachine" and that was a TreePicker by default. I can also add both the TreePicker aswell as the ValuePicker, and only the ValuePicker seems to work then. But again, the TreePicker is the default at creation, so "not supported" would be strange...
I also found another post about the valuepicker or treepicker.
https://communities.vmware.com/t5/vRealize-Automation-Tools/vRA-8-1-HF1-Workflow-forms-not-rendering...
It seems that in older versions the treepicker is automagically changed to a valuepicker
as TimDScott explains in his issue.
However, in my case with 8.2p1 it IS displayed as a TreePicker and not converted to a ValuePicker.
That suggests that the ValuePicker would be just fine, which it is not.
(however, indeed, when creating a Custom Form, the field is changed to a ValuePicker, but that is not what I did. I just use it as it is created and then it does start the TreePicker)
@xian_ your link also says: "For the tree picker, you can provide a default value by configuring an external source."
So I guess the tree picker should be possible. But I do not understand what VMware means by that line.