it is bad UI

Can you clarify?

(In reply to :Paolo Amadini from comment #1)

Can you clarify?

Sorry, I changed summary.
There are no description in the placeholder.
There are no context menu about creating a new pref.

I agree that if the page is approached specifically with the task of adding a new preference in mind, it might be unclear what the next step is when the search text box is shown.

While a better interface might have a separate section to add new preferences, updating the text in the placeholder might indeed help for the essential interface we've implemented here.

:paolo, is this a regression or an enhancement request? If it is a regression, do we have a regression range?

As a "future goal", I proposed a button opening a modal in the mockup.
Maybe it would be worth to implement this change before the beta version is released.

Paolo: How difficult is it, to check if a modal is opened etc? You said that this would be rather difficult.

(In reply to Neha Kochar [:neha] from comment #4)

:paolo, is this a regression or an enhancement request?

Enhancement request.

(In reply to :Matthias Kammüller from comment #5)

Paolo: How difficult is it, to check if a modal is opened etc? You said that this would be rather difficult.

Yes, as we discussed before this would be quite difficult, and I would do it for this page only if we need the same support for other in-content pages.

For the moment, updating the text in the placeholder should work. We might do this as part of bug 1524779 so we only change the string once.