Start-Process -NoNewWindow switch does not work properly in ISE
When you use Start-Process with the -NoNewWindow switch, it is supposed to direct any stdout from the process back to the powershell console that you called Start-Process with. This works as expected when you run the command from the regular PowerShell console (whose Name is "ConsoleHost"). However, if you run the same command from PowerShell ISE (or other IDEs such as PowerGUI), no output is displayed.
I have observed this bug using PowerShell v5; I'm not certain if it is present in previous versions of PowerShell or ISE.
The bug is also mentioned in a few other places on the internet: