There is an XSLT List View web part and I want to filter data by Filtered Lookup field. What is a proper way to do this? When I click "Edit the current view" of web part and filter by this field it doesn't show anything.
I do not have any experience with the "Filtered Lookup" add-in, but it interested me, and when viewing the page you linked, I noticed that it appears that you are supposed to set the filter on the Field Edit page for your Filtered Lookup field; not by setting a filter on the current view, as you would with an OOTB field type.
I attempted to insert a screenshot, but apparently I need at least 10 points to insert a picture, so you're out of luck!
If you go here: http://filteredlookup.codeplex.com/
and scroll to the bottom of the page, it shows 2 examples of the types of filters you can set on the Field Edit page.
Hope this helps.