I do not understand "Nominal Row Filter Widget" behavior in a Component

Dear Knimers,

I fail to grasp how the “Nominal Row Filter Widget” is supposed to work.

Suppose I have this workflow:


The component contains:

The Table Creator generates the following table:


When I run this workflow, the generated view is:


So far so good.

Now I deselect “Cat”, and click “Apply”. I expect the green dots to disappear, but nothing happens:


I anything happening at all? Let’s change the component a bit:

with the following Java code:


Let’s clear the console and run the workflow again from scratch. As expected, I get the following output in the console window:


Now, deselect “Cat” again and click “Apply”, just like before…


Yep, obviously clicking “Apply” in the component view window triggers Component re-execution, as one would expect. However, somehow the view is not updated. Is this normal or is this a bug? And if this is normal, what is the philosophy?

If I close the view and open it again, suddenly the “Cat” dots are gone (also the color of the “Dog” dots changed, but that’s a different issue):



Attached the example workflow: KNIME_project9.knwf (13.8 KB)

Of course, I could also simply look at the output of the Nominal Row Filter Widget directly. After the first execution it looks like:


I can now open the Scatter Plot window separately and open is side-by-side with the Component view window. At this point they are identical:

After deselecting “Cat” and clicking “Apply”, it output table of the Row Filter Widget changes to:


Interestingly, the Scatter Plot window is automatically updated upon clicking “Apply”, but the Component view window is not, even though my clicking took place in the Component view!

I see now that I can get the desired functionality with the “Interactive Value Filter Widget”. But I still wonder what the purpose is of the Nominal Row Filter Widget if it does not result in an updated plot…

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