Dashboard Dropdown button - how to extract options in the downstream

hello
Newbie here
.I have a simple dashboard based flow.
It contains a dropdown node, a button, and a python module I do some back ground work and an output debug node.
My problem is for an injection node (non-dashbooard flow), this sequence works fine.
For Dashboard's Dropdown, I select various options from the ui frame (localhost:1880/ui).
I dont see them displayed if I add a debug node right after dropdown menu node.
nor I can not get them via msg['payload'] in my python module.

what am i missing here?
any help please?

here is my flow:

Dropdown Menu --> (On UI page: user will select a bunch, and click submit)

In the node red editor:

Dropdown node --> Button node --> to my custom python node

For my custom python i am using node_red decoarator, which works fine.

The debug node is your friend! Put a debug node (set to display the complete msg object) on the output of the dropdown node and another on the output of the button node.

Now what do you see?