What are the 4 white dots in a MIDI track view?

[RobertWS]

I spent 40 minutes trying to find the answer but couldn't.

In MIDI tracks, what are the four white dots (circled in red) that appear, apparently at random, in MIDI tracks?

 

[msmcleod]

That's telling you that if you double click on that clip, it'll open the PRV.

You can change the default in TV Options->Click Behavior->Double Click->Midi Clips

The Optons are:
Nothing 
Clip Properties
Event List View
Staff View
Piano Roll View
Inline Piano Roll View

Long holding the left button down will show a pop-up menu to change it for individual clips.

Set it to Nothing if you don't want those to appear.

[Colin Nicholls]

That's the clip menu icon. All clips have them, it's not random.