This is actually a feature in DP's merge command. When merging information from one track to another that contains the same controller information, this information may be ignored. With an on/off controller like 64 (sustain), if merged controller appears before/after an existing controller, this merged controller value will be ignored. The reasoning behind this is to avoid opposing controllers being merged within a track. For example, if you have two tracks to be merged, one with a volume controller stream going upwards, the other going downwards, the playback effect will most likely not be desirable.

If this is desired, here's a way to include this controller data for the desired MIDI channel:

1. After recording to your MIDI tracks, create a new MIDI track with the same MIDI channel and output as the desired playback track.
2. From the basics menu choose set view filter. Hit the clear button and choose to view controllers only. The tracks overview window will display only controllers. You can move this information around in the tracks without effecting the other data, not visible since choosing this view filter.
3. Move the MIDI phrase selection that contains the controller information to the desired location.
4. Go back to the set view filter and select all. Select the notes to merge with the track, hit copy from the edit menu, select the desired location and choose Merge from the edit menu.

These steps allow you to isolate the view to just look at the controllers and edit them in the tracks as you see fit. Sending the controllers to the same channel and output will allow playback of opposing controllers.