Double-clicking on a rackspace name (or choosing the Show Rackspace Properties... menu item from the contextual menu) opens a dialog that displays rackspace properties:
Name - to rename the rackspace, type a new name here.
Override global tempo and time signature - turn on this toggle button if you want the rackspace to have its own tempo value and time signature, then enter the desired BPM (beats per minute) and time signature. If this toggle button is turned off, the rackspace will use the global tempo and time signature information.
Sync tempo with external MIDI clock - turn on this toggle button if you want the rackspace to adjust its tempo from incoming MIDI clock messages (24 ticks per quarter note) sent from an external device, thus enabling echo/delay or arpeggiator plugins capable of receiving MIDI clock to be automatically synchronized with your external device.
Maximum audio tail length - sets the maximum time before a sound is cut off when you switch rackspaces. The maximum length is 10 seconds. Often known as an audio "tail", this feature is useful when using effects such as reverb or echo. In Gig Performer 4 you can select Input muting and Output fading:
Input muting - move this scroll bar to select the desired number of seconds (up to 10s) in which input to this rackspace will be smoothly silenced.
Output fading - move this scroll bar to select the desired number of seconds (up to 10s) in which the audio output of this rackspace will be smoothly faded out.
MIDI Patch Persist - if this feature is checked, whenever you switch to another rackspace, notes that you are holding (either directly on your keyboard or via your sustain pedal) will continue sounding until you release the keys or the pedal. This feature works with any number of rackspaces, up to the limits of your system's available RAM and CPU resources, so you could conceivably keep the sound of five or more rackspaces going simultaneously.
If this feature is unchecked, whenever you switch from one rackspace to another, the sound of the previous rackspace is immediately silenced even if you are holding notes down or have pressed the sustain pedal.