This is yet another bug in -persist
handling on Windows. If gnuplot is invoked with the --persist
option but no interactive graph window is opened in that session, this will result in a zombie process.
This is particularily relevant, since double clicking in Windows explorer opens gnuplot scripts that way by default.
Applies to 4.6 and 4.7 branches.
See also https://sourceforge.net/p/gnuplot/bugs/1335/
Fixed in the 4.6 and 5.0 CVS branches.