==========================================
ALL PROJECTS
- Tempo 133 at 0.0.00
- Tempo Change 100 at 33.1.00
- TimeSig 4/4

Obviously inserting empty space across a tempo change is not working as expected.
- It results in measures after the insertion to no longer be snapped to the grid.
- In some cases the items are truncated.
- It is expected that inserting empty space will do no more than sliding everything to right, to the end of the inserted space. 

==========================================
reaper_tempo_grid_timesig_02a

- A 2 beat MIDI item has been copied to the end of the song.
- Markers for where the empty space will be added and for where the temp change is.
- 8 measure region starting at 29.1.00.
- Marker for the tempo change at 33.1.00
- End of insert is 37.1.00.
- All snapped to the grid.
- ALL MIDI items are 2.0.00 in length.
- All good.

==========================================
reaper_tempo_grid_timesig_02b

- 8 measures of empty space inserted at 29.1.0
- All MIDI items moved to the right 8 beats
- The original tempo change to 100 is still at 33.1.00.
- There is a new added tempo change to 100 at 40.1.030075.
- This temp change is not snapped to the grid.
- The beginning of the first moved MIDI item is snapped to the grid.
- This first MIDI item shows a length of 1.2.02 in the item properties.
- The first MIDI item is indeed much shorter, truncated by almost 2 beats.
- This second MIDI item shows a length of 1.2.02 in the item properties as well.
- The beginning of this item is not snapped to the grid, but is snapped to the end of the previous item.
- The end of the second MIDI item is the time of the newly added tempo change at 40.1.030075.
- The third MIDI item after the inserted empty space has been restored to a correct length of 2.0.00.
- All further MIDI items are 2.0.00.
- None of the rest of the MIDI items are snapped to the grid.
- All are equally off by .03 late as seen in the item properties.
- The region properties align to the measures, and are no longer snapped to the grid.

It's obvious that inserting silence is not simple adding silence, but adding new tempo changes (even if the same), truncating MID items, and re-placing items off of the grid.

==========================================
