BUG ? Project time was set to a fixed value but keeps changing values randomly

I have recorded a rock-song that is about 04:15 min long and set the project time in the Cubase settings to 04:20 minutes to have an optimal view when I zoom out the whole project. I know that this project won’t be any longer, all parts are already recorded.
What I don’t understand: the project time expands randomly. I don’t know what I could have done to make the program add another 8 minutes for example. I only see it when I zoom out. Then I go to the settings again, notice the new project time has been set to e.g. 12 minutes, set it to 04.20 again and get back to working in the project window. But after a time it happens again, and I can’t see why.
Am I missing something? Can I lock the project duration anywhere?


The Project Duration changes only, if you record or move/copy any object behind the border (duration time) of the project.

Thanks, Martin, for your fast reply and the explanation.

I can exclude recording because I didn’t record anything. And I still don’t know how I can move an object behind the project time border. I moved objects from one track to another track vertically in the project, not horizontally.

I did this now:

  1. Project time is set to 04:20 min
  2. I go to the middle of the project (minute 02:10) … drag a two-beat-audio part (a small part that has a range of 2 beats) from audio track 10 and drop it on audio track 11 at the exact same timestamp.
  3. I zoom out and Cubase has added - without asking me - approximately 1 minute to the existing project time.

WHY ???