The function for Lock the clip with an absolute time does not work. I lock data and positions in absolute time but then, if I create some tempo changes, the absolute position of the notes moves in any case. Why?

Specifically, I am talking about midi clips  (I set the clip properties on H:M:S:F and absolute time). If I create the changes of tempo, in tempo map, should change the notation, not the absolute position of the midi events, I think.

Hi, and welcome to this forum.
Try to bounce the MIDI clip to it self, before changing tempo.
All the best.

Thank you very much for the reply. However, I speak English as a Spanish cow. What does it mean, in other words, "bounce the MIDI clip to it self"? 
I've also tried copying the locked clip and pasting it into another project, but absolute time is not saved.
However, the manual says:
 
"If a clip’s position is locked, and you change tempo, what happens to the clip’s position depends on what option the Clip Properties Time Base field is set to: Musical (M:B:T), or Absolute (SMPTE). If the clip is set to the Musical time base, the clip’s M:B:T position stays constant, and its Absolute position shifts. If the clip is set to the Absolute time base, its Absolute position does not move, but its M:B:T position shifts."
 
It's very simple but, it seems to me, does not work. If I change tempo, in any case, M:B:T position no shifts. Only the absolute positions of the events are shifted. Is it a bug in the program?
 Thanks so much for any advice..

Right click on the clip, and choose bounce to clip.

Thanks. I have the Italian program and I did not understand. Anyway, I think the 'bounce to clip' command works with audio clips. It seems to me that there is no solution ...

Bounce to clip works with MIDI as well. 
Did you try?

I tried but I did not solve anything ...

Did you unlock the Clip before bouncing?

Yes, I've tried everything but the result does not change ...
But are you sure it works? The manual does not say that it is necessary bouncing the clip...