ctrl+j, ctrl+j - visual filter selected only

[joeking]

I am not sure what's happening.
I first select a file and then menu - view/visual filter/selected only
and only the file is shown.
Okay.
I then go ctrl+j. I get most of the files/folders but not all - looks like the files/folders are selected according to extension if a file or just folders and no files (e.g I just select a file with a .pdf extension, it was the only one in the director, after ctrl+alt+j I get just the .pdf file. Then I go ctrl+j and I get just the directories and no .pdf, do ctrl+j to get every back to normal.
e.g. 2. a .flv file is selected, there are 3 in the directory, ctrl+alt+j to select just the one, ctrl+j gives the rest of the .flv files. ctrl+j again to restore to normal and view all
)

Can someone explain what is happening?

[nikos]

the first time you hit ctrl+J it's like you had all the files shown and then you reuse your last filename filter (check what the addressbar writes at the very end). The second time you press ctrl+J you show all files

an alternative more straightforward way to escape from "view selected only" filter is to use View | Show all