It seems like sometimes the drop-down functionality is broken in Piwik 1.4:
E.g., in my dashboard I have the search-term widget and it looks like this (after expanding the options):
Keyword1
+--Google (links to Keyword2)
Keyword2
+--No data to display
The same goes for the visitor country (GeoIP) widget:
Germany
+--New York
+--Washington D.C.
USA
+--No data to display
I just had this issue when I head only two entries in each widget.
Now there has been an additional visitor and everything works fine again…