- What Grafana version and what operating system are you using?
Grafana v10.4.2 (22809dea50), Alpine Linux v3.19
- What are you trying to achieve?
I have a dashboard, with three variables, two are text inputs, and a third is a dropdown using a query from our custom datasource. The third variable is depended n the other two. The first two variables are hidden on the dashboard (but can be made visible for debugging)
Now, I want to embed the dashboard in an iframe, so that the first two variables are delivered via query parameters (var-…=…), and this should let the dashboard populate the third variable when it loads, so that the user can make a selection there.
- How are you trying to achieve it?
Well, exactly how I described above 
- What happened?
The two variables provided via query parameters are recognized, at least, when I make them visible on the dashboard, they are correctly displayed, but the dropdown that depends on the two, does not update an does not execute a data source query to fetch the drop-down list contents.
This does work, as soon as I manually change one of the two variables (when visible).
- What did you expect to happen?
I expect the dropdown to load its contents from the data source on page load.
- Can you copy/paste the configuration(s) that you are having problems with?
Not really, given that we have a custom data source. I also don’t know if this has something to do with it, I somehow doubt it does, but who knows…?
- Did you receive any errors in the Grafana UI or in related logs? If so, please tell us exactly what they were.
No error messages
- Did you follow any online instructions? If so, what is the URL?
I’ve checked the docs on variables but didn’t find anything helpful there