SourceNavigator crashes when adding directory to an existing project?

[Deborah Briggs]

Hi - I'm running SourceNavigator 4.5.2 on Linux, it crashes (screen freezes
under X windows, can't redraw, doesn't respond to commands but doesn't exit
the app either) when I try to add a directory to an existing project but
doesn't crash if I add files individually.  Any advice appreciated, adding
files by hand is incredibly tedious.