However, since you would like to be able to select ALL the values in the Action Dropdown, may I ask why you use a parameter and an Action Dropdown at all? If your use case is such that it works fine loading all data that matches any of the parameter value options, you should be able to use an in-memory filter instead, where you do have the Select All. This is basically the logic behind the decision to not have a Select All option for the Action Dropdown: When using a parameter and an Action Dropdown, it is because the data volume does not allow that you load ALL data.
I hope this can give you some ideas for alternative solutions.
Best regards, Theo Klemming
Thanks for your answer Theo,
I use Action Dropdown more than filters because in parallel I need to show Top 10 list depending on the selection I make.
For example I need to show the Top 10 clients depending on selected markets or countries.
As this dynamic Top 10 doesn't seem possible in Datawatch, this is done in the back-end by passing the selections in parameters.
OK, with your need for the Top 10 functionality, I can see your need for using parameters.
The good news for you is that we have that type of "dynamic" top-10 filtering on the near-term development road map. When that is generally available, it should meet your needs while allowing you to work with a filter instead of a parameter.
best regards, Theo Klemming