Describing advanced MIDI editing in Temper is an awkward affair -- the power comes through the collection of tools, which can be dynamically added and are dependent upon the various shapes for their behaviour. The only way to really become a proficient MIDI editeer in Temper is to learn the tools and how the shapes affect each one.
That said, there are commonalities and clear design decisions that can be explained and will give you a jump on where to start: Most tools include a shape view, and there are a set of four tools called the intrinsics for altering the basic note properties.
The Temper piano roll displays both the current active track, as well as any other MIDI tracks in the song. These other tracks can be filtered two ways: Either with the shadow control described above, or by using groups to choose exactly which tracks are currently displayed. Beyond simply displaying other tracks, though, Temper has another function: You can activate any number of tracks for simultaneous editing.
There are two ways to activate multiple editing tracks: Either select it in the title bar while holding the SHIFT key, or select it with the Select Track tool while holding SHIFT.
As you activate tracks, numbers will appear next to their names in the title bar. All tools operate on multiple tracks just like they do on single tracks: Select will select events across multiple tracks, Wand can adjust the velocity of notes in multiple tracks, Quantize will quantize all events in all tracks, etc.
Performance time is a way of offsetting specific notes so they play back before or after their current time. You can set a performance offset time either via the inspector panel of a single note (or multiple notes), by engaging the perform time grid (found between the key and time grids in the track editor) and using tools such as Shif-T, or by engaging the perform time grid and directly editing the notes with the pencil tool.
Performance time provides some interesting possibilities: Because it dissociates playback time from sequence time you can have notes that overhang their phrase boundaries, for example lead-ins, but your phrases are still locked to measure boundaries, so they're easy to move in the arrange area. It can also be used as a way to humanize a section of music while still maintaining the strict quantizing that makes events easy to move and notate.
One tip is to turn on the perform time grid and use the Quantize tool on a selection of notes that was performed by hand: The notes are quantized, but the actual performance time remains the same, so you can organize your performance into measure-aligned, easy to manipulate phrases without losing the human performance.
Another tip is to select the "Alter performance time when ALT is held" preference found in Setup->Behaviour. When this is selected, then holding down ALT in the track editor will do two things: Turn on the performance grid while simultaneously turning off the time grid, allowing you to do a freeform move of the selected events. This allows easy, minor tweaks to time without losing quantization.
NOTE: The workbench is currently not being maintained, and might be removed in a future release.
The Workbench is a powerful mode used to apply one or more tools to existing MIDI data. After you have selected the events you wish to process, press the Workbench button to enter workbench mode. This will disable inappropriate tools, but you can click on any number of the remaining tools to chain them together into a complex supertool. All selected tools are constantly processing the events, but the controls for only one tool will be active at a time, which you can switch between by using MIDI macro Select. This allows you to activate any number of tools, then move to your MIDI controller for complete access to all the tool parameters.
Remember that you can have multiple tracks activated for editing, as described above. Workbench mode will operate on selected events across all active tracks. As a minor example, this means you could take a four-track drum rhythm and activate the Velocirapture tool across all the tracks for rapidly adding a little subtle variation in velocity.