Vel Limit field: The two values of the Vel Lim parameter define a velocity range. All notes with a velocity that falls outside this range are not played by the instrument.
Delay pop-up menu: Causes all MIDI events to be sent early or late, allowing you to compensate for any differences in reaction time between your various MIDI devices. Use the Delay parameter (in the Track inspector) to create rhythmic delay effects, as this allows longer delay times.
No Transpose checkbox: If selected, all regions on any tracks played by this instrument object are protected from transposition. In other words, the Transpose Region parameter is ignored. This is very useful for instruments assigned to drum or other samples—mapped across the keyboard on a single MIDI channel—as transposition triggers different sounds (rather than pitches) in these instruments.
No Reset checkbox: If selected, no reset messages are sent to the instrument. This can be useful if controllers are being used for nonmusical purposes, such as when using the instrument object for Mixer automation tasks. The Logic Pro > Settings > MIDI > Reset Messages settings determine which reset messages are sent. These messages are not sent to No Reset instruments.
Style pop-up menu: Can be set to any of the available staff styles. Whenever a region is created on one of the instrument’s tracks, it’s assigned the staff style displayed here. If the Auto style is chosen (the default), Logic Pro picks an appropriate style based on the pitch range of the notes in the region. For more information on staff styles, see PDF
Control Surfaces Support Guide: PDF