Error in function QFList when calling

[Marco-Israel]

My vim setting:
set completeopt=menuone,popup,longest
set previewpopup=height:10,width:60

According to #23 I also set
like let g:quickr_preview_position = 'popup'

Here my error (true in german .., sorry :( ) output when calling \leader space.
|| Fehler beim Ausführen von "function QFList":
|| Zeile 32:
|| E441: Es gibt kein Vorschaufenster
|| Zeile 44:
|| E366: Popup-Fenster zu betreten nicht erlaubt

[Marco-Israel]

uncomment out
set previewpopup=height:10,width:60

will resolve the error but popup does not work