Show Cue System

I think it will be useful if SCS could refuse incoming midi input from specified channels.

For ex: I connected my midi keyboard to send start and stop on ch16 but SCS receives messages from all channels and sometimes it displayed a "stack overflow" alert.

Good idea. The MIDI Input handling already extracts the MIDI channel for relevant MIDI message types (eg Note On/Off, Program Change, etc) so I've now built in a filter to ignore any such message immediately if the channel number is not one of those identified in the properties for Cue Control MIDI devices. This filtering takes place prior to the code that places incoming messages on a stack for processing by the main thread. It was this stack that had overflowed. I'll let you have a pre-release of this new version when I've completed another change I'm currently working on.