01. Open foobar2000 (0.9 beta 11)
02. Go to Foobar2000 > Preferences
03. Go to Media Library
04. Select Autoplaylist
05. Click Activate
06. Close [X] the window
07. Close the Preferences
08. Go to Foobar2000 > Preferences
09. Select Autoplaylist
10. Click Activate

Nothing happens. You have to exit and reopen foobar2000 in order to get back to the Autoplaylist window.

Is it just happening for me?

Reproduced.

When I click previev button in Autoplaylist dialog and the query string contains only character ':', after quiting the foobar, I get warning message which says 'metadb_handle leaks: xxx objects' where xxx is a number.