Hi All, I've recently installed latest x-Cygwin on different PCs and suddenly discovered strange reaction on 'system' function inside Perl/Tk apps. Naturally, console applications running well with this function. Below you can see my snippet code and stuff it prints. FELIX-XP cat test.pl #!/usr/bin/perl # Code automatically generated by VPTK_W use strict; use Tk; use Tk::Button; my $mw=MainWindow->new(-title=>'Bug demo'); my $w_Button_001 = $mw -Button ( -background=>'green4', -foreground=>'Yellow', -text=>'Exit', -command=>sub {exit} ) -pack(); my $w_Button_002 = $mw -Button ( -background, 'Yellow', -foreground, 'Black', -command, sub{system('echo Hello'=>'')}, -text, 'Magic 0' ) -pack(); my $w_Button_003 = $mw -Button ( -background, 'Red', -foreground, 'Yellow', -command, sub{system('xterm'=>'')}, -text, 'Magic 1' ) -> pack(); MainLoop;