@MarcoFalke what does "Don't show integer progress in progress bar. (Already shown in front
of progress bar)" mean? What change is it?

I see something like this with the current master:

@paveljanik By default it shows the percentage twice: #8371 (comment). (Maybe not on osx)

Thanks for doing this.

Question:

Remove the "Progress increase per hour" information, as it is
redundant to the already displayed information and sounds potentially
confusing.

Where is the information already visible?
Why is it confusing?
IMO "progress increase per hours" is the only information which could one allow to get a feeling of how-fast he/she is currently syncing. But no strong opinion.

@MarcoFalke Aha! Thanks. Yes, I do not see it here. BTW - the progressbar on OS X doesn't show, what is 100%, it is a bold line showing nothing.

Maybe we need to distinct the percentage information over PlatformStyles in order to not just display a non-value progress bar.
Or maybe there is a QT setting to not display the percentage information on a progress bar.

@jonasschnelli Example: If you are synced 90% and the "Progress increase per hour" is 10%, then the estimated time until synced is 1 hour.

Or: If you are synced 0% and the increase is 100% per hour, the estimated time is 1 hour.

@MarcoFalke: I just though, the "Estimated time left" doesn't allow you to directly get a feeling on how fast you are syncing (in a comparable manner).
IMO most information on the screen is redundant (except of maybe the last-block-time).

Closing for now. (Too controversial)

What about the nPowTargetSpacing change?
My understanding is, that once we have the headers-only-chain complete, we can give an adequate information about the remaining amount of blocks.

@jonasschnelli: As I understand your code, the gui may miss headers sometimes, so you added the "fHeaders-shortcut" to make sure the gui always knows the best header. Though, it seems a waste of resources to do this the way it is now: First, lock cs_main for each header, then drop the header if it is older than 30 days... This seems wasteful to me.

I don't think we should assume the gui knows the best header at all time. Thus, I removed the "fHeader-shortcut" in #8821. Please have a look at #8821 to see if it makes sense, we/I can do the gui polish in a later pull next month. The unresponsive gui is more important to fix now.

Yes. I think #8821 makes sense. Will test soon.