Well, yes, it's odd, but does it really matter? If so, why?
This situation is problematic because it sits outside normal Tableau space—that set of configurations and behaviors that constitute the standard Tableau interface. By presenting an abnormal configuration that confounds expectations Tableau confuses the user, which in turn leads to, at least: time wasted in trying to recover from the situation (even if it's not strictly a fault or problem); effort and energy spent trying to understand what's happened, and why (some users won't care, some will dig into it until the mystery is fully solved); and a sense of mistrust, a suspicion that Tableau isn't as simple, straightforward, easy, and reliable as it could be. It's the accretion of these elements that ultimately undermines the whole product.
Why should I—or you—spend any time figuring out what's going on here? Particularly if it's not really a going to cause Tableau to crash, do something erroneously, or be a major usability problem.
Fair question. I've found that chasing down these rabbit holes reveals a lot about Tableau, how it's put together and how it works, and this deeper understanding leads to being able to use it better. And it's fun, in the way puzzling things out is.
Creating your own Phantom Parameter. It's really not all that difficult, just follow these easy steps.
As an interesting exercise, go ahead and try this:
- Hide Parameter 1
use either the "Analysis|Parameters" menu or select the "Hide Card" option from Parameter 1's context menu (via the down-triangle glyph visible when you mouse onto Parameter 1).
- Once Parameter 1 is not visible, save and close the workbook.
- Now re-open the workbook — Parameter 1 isn't visible, nor is there a Parameters panel in the Data Window.
- Select the "Analysis|Parameters" menu option. There's Parameter 1, ready for presentation.
What's going on here?
The short version is that Parameters were implemented as a special of data source internal to the workbook. This makes sense from the perspective of the implementation being able to leverage Tableau's existing data management mechanisms, but it has consequences that are sometimes less than optimal for the Tableau user.
Is this dangerous?
Given this odd behavior, what does this mean? Does it signal anything about Tableau that's dangerous, or could cause problems for ordinary Tableau users?
Not to worry. This one little wrinkle doesn't, as far as I can tell, indicate that there's anything amiss that is cause for real concern.
It is, however, a manifestation of deeper, substantive aspects of how Parameters were implemented in Tableau that do have consequences that surface in different places. I'll be examining these in future posts.
A better design proposal.
The basic problem with Parameters that this situation reveals is that they've been implemented as a shadow data source that's only partially surfaced to the Tableau user interface. We've seen here one scenario in which there's the opportunity for real confusion, and confusion in a UI is invariably a bad thing.
It would make sense if parameters were first class Tableau citizens. The set of Parameters should occupy their own space separate and apart from the data sources. This would alleviate the situation of the name "Parameters" not being available for a user-named data connection.
As Parameters have an existence apart from other data sources— e.g. they persist in a workbook even if no data sources exits, they should be represented in the UI separate and apart from data sources. I think I see why their presentation within the Data Window might have seemed to make sense when Parameters were introduced, but it's one of those things that needs to be adjusted so that the UI accurately reflects Tableau's components' semantics. The counter-argument is that this would overload and complicate the user interface, that they're working OK as implemented, and that there's no real cry from the user community to change the way things are. This is a powerful argument, one that hard to contest. It's also the "things are good enough" argument that's led many once-successful endeavors down the path to obsolescence.
Clearly, improving how Parameters are handled in Tableau isn't likely to be trivial, and it may have wide ranging implications, up to and including reconsidering the set of uses they're put to and contemplating whether there isn't a better way to satisfy these needs. The specter of complexity is an inhibitor, but Tableau would be a better tool if at least the wrinkles identified here were ironed out.