Confirmed in v2.15.x

Looks like it's because of the "sequencing" thing; if you disable the far-right-hand tool in the "timeline" this will no longer happen.

It's debatable whether this is right; it's certainly surprising. I'm not sure what's the best thing to do...

1. turn off "sequence" on the first edit of a value in the "timing" tab? or
2. stop timing tab edits from triggering the "sequencing" action afterwards? or
3. something else?

Any thoughts?

Okay, I'll play around with this a bit and try to agree towards something with myself ;-)

For what I was doing in this case, it was annoying. Maybe in other cases it will appear just right. It's just an irritation if a value changes unexpectedly. It appears that 'sequencing' is enabled by default. Hmm. While I remember using it occasionally, I think I never thought enough about the inner workings of that option.

I think turning of sequencing when manually adjusting position values as you suggest under 1. should be a good idea. As one would think that when shifting stuff around manually, you don't want that to happen automatically. And it is better to show that by disabling the icon than to have it happening only under obscure conditions?

Great. The original intent of "sequence" (if I remember right) was to support the use case of (for example) adding a bunch of PNG slides using the "add content" button. Then you could remove one, and the others would stick themselves together.

You could perhaps argue that anyone who is adding more than one thing to a project should be happy using the timeline, in which case maybe "sequence" could be removed altogether. Though it is always rather tempting to solve a problem by taking the problem away altogether ;)

At some point during this thought process one might ask: what's the point of the content list anyway...!

Hmm. Playing with it, I just notice that when I shift a piece of content graphically in timeline view, sequencing is disabled automatically. So, why not do the same when adjusting values in the position tab?

BTW - should I file a mantis entry for the hardly visible icon change in timeline view? It is nearly impossible to detect the difference between sequencing on/off, at least in Mac OS.

Pfff... here I am, with three PNGs in a row. Now, when in this case I adjust play length of one - I would indeed prefer sequencing to stay on, because 'typically' I don't want black holes...

Maybe my issue is only with the first object? Or in general with a single piece of content?

Let me think about it. Good to know it's not an actual bug but can be worked around ;-)

I regularly do 'obituary slides' with some music and there usually shift fade in/out picture against the music, so I adjust in-time vs. play time until it fits my preference.

I think it is only an issue with the first piece of content - while it is typically expected for multiple pieces to stay joined together, it is quite probably not expected for the first piece to be shifted towards zero? That is, for those of us who create blacks or silence by leaving out content ;-)

Well spotted on the "first drag" thing - I think that was a conscious decision; if you drag something in the timeline you "know what you are doing" and so the sequencing is turned off.

It's a tricky one, for sure - what if I add content A, B and C then remove A? Am I right to be surprised that there's a gap where A used to be (if we special-case auto-sequence to not work for the first piece)?

PS with respect to icon changes in timeline view - yes, please do file a bug - the icons desperately need work!