There isn't a "Sequencer" window, however you can import your MIDI file such that all of the channels are separated onto different tracks. Instead of using File | Open (which imports the entire MIDI file onto a single multi-channel track), use "File menu | Import | Import Melody from MIDI file". Ignore that the menu item says "import Melody" - it can be used for all parts.

In the Import MIDI file dialog that comes up, it will automatically detect the different channels in your MIDI file and give you the option of assigning a different track for each channel. Go through the list of channels and assign Utility track #1 for the first, Utility track #2 for the second, and so on - you might have to scroll down to make sure you see them all.

You'll then have all of the channels separated on individual tracks and you can mute / solo / view them just like the other tracks. If you want to disable the BiaB style parts from playing, you can either click on the Style name and uncheck "Style is enabled" (like what's done automatically when you open an entire MIDI file using File | Open), or you can disable the tracks individually (right-click on the track | Track Settings | track is enabled - uncheck)

Andrew
PG Music Inc.