Canvas dropdown control doesn't work as I expected

I try to create a dropdown control inside the canvas. I created a data source and previewed it:

And next, I tried to set up the display for this control:

image

But nothing was displayed on the canvas when I clicked on this control:

Who knows what was wrong and how to improve the configuration of this control so it can be able to display needed data?

I found such a thing in the Kibana documentation

I don't understand, why in this query string after var keyword value of variable indexName is used instead of indexName variable? It makes no sense with the concept of variables.

I tried to apply that approach to my canvas dropdown control, I switched to query expression and I wrote my query using the above concept:

What is wrong? Why there is no error description? I found canvas designer very poor. Why my the dropdown control doesn't have expected data from the SQL query?

I think you are right - it looks like there is a bug in the 2nd screenshot in the documentation. I don't know why else it would look like var "my_new_index_name".

I'm not seeing this problem you describe. It may be something with the data source or a filter on the worksheet.

I don't think having a variable in the essql query will help - it sounds like you don't have the same use case that is covered in that section of the documentation.