2 Issues both related to query based drop down please read below documentation for more info:

https://docs.microsoft.com/en-us/azure/databricks/sql/user/queries/query-parameters#query-based-drop...

Issue # 1

Drop down list only accepts up to 400 values

Only affects parameters which are a name/value pair

After 400 values, the drop-down box glitches out, displays duplicate values and user is unable to scroll

Issue # 2

Query based dropdown selects multiple values when user only selects 1

Only affects parameters which are a name/value pair

If the value is not unique to the name (see example), when user selects the parameter multiple other names are also selected as a multi-select, even when user only wants to select 1

Attached repro steps and screenshots.

Please reach out if you need more info