Hi, I'm using Pd-0.48-test3 on Mac OSX 10.11.6.
I found out if I create a Hslider using the shortcut 'Command + Shift + h', the Pd window hides in the background.
Other shortcuts seem to work without the problem so I guess it clashes with the Mac's OS shortcut 'Command + h' which is used to hide the windows of the front app.
I didn't have this issue on Pd-0.47-1 and I hope this can be fixed in the stable version of Pd-0.48.
Thanks,
Zack