Midi Controller data "forgotten" after about 1 1/2 minutes

I've tried it, and yes, controller value doesn't show in PRV, but lookback is still working here. Maybe there is some specific situation?

The correct description should be: "Continuous controller horizontal handle disappears 64 bars past the last controller entry".
 
Some facts based on empirical evidence from testing with CC #7 (Volume) and the TTS-1 soft synth:
1.  The CC event still exists and does not disappear.
2.  The CC horizontal handle no longer displays when the measure in the left margin of the PRV is over 64 bars past the actual CC event.
3.  The 64 bar handle length is constant and not affected by clip length, tempo, time or PRV zoom level.
4.  The Controller Searchback Before Play Starts option functions as expected regardless of the disappearance of the CC horizontal handle.
 
Test method:
1.  Start new project with Normal template
2.  Drag TTS-1 into project from Browser and check MIDI Source, First Synth Audio Output, and Synth Property Page.
3.  Select MIDI track and open Piano Roll View (PRV)
4.  Click "+" in CC lane in PRV and add Control 7: Volume [PART 01] from MIDI Event Type dialog
5.  Insert a CC #7 with a value of 30 at bar 1:1:000.
6.  Slip edit the new clip created by step 5 in the Clip pane to bar 100.
7.  Scroll the PRV until bar 65 passes the left margin of the Notes pane and the horizontal handle for the CC no longer displays in the PRV CC lane.
8.  Set the TTS-1 Volume slider in Part 01 to a value of 100
9.  Set the Now time to bar 80 and start playback.
10.  Repeat steps 8 and 9 at bars 70 and 90.
 
Expected results:
The volume in Part 01 in the TTS1 should immediately change from 100 to the entered CC value of 30 at the start of playback.
 
Actual results:
The volume slider in Part 01 immediately changed from 100 to 30 at the start of playback  [PASSED]
 
Conclusions:
This is a display issue only and does not affect the function of the controller event or Controller Searchback.