in reply to Re^2: 'system' hangs in a Windows Tk app
in thread 'system' hangs in a Windows Tk app

Tk could be considered old-fashioned, but:

On another point, if "old-fashioned" Tk is denied by end-users of software, you can actually use *any* GUI toolkit from Perl.
I, for one, started from using Perl from within C++Builder GUI, but then, step by step, I switched to something more powerful.