Something strange is going on with theme customizations; what I’m seeing in that video is definitely not a default – especially the odd full-width of every post. I believe the default theme here (by default, I mean what you get if you sign up with a new account from scratch) is actually “Straight Dope Light”. Can you try that one?
I recreated it on discourse-classic on my work laptop. It has the scrollbar and white space on the sides. Can upload video of that if needed.
I haven’t been able to recreate it on straightdope light yet. Have tried a few times.
I’m virtually certain this is a theme issue. What’s in that video is… really weird. Full width content, etc. I think the naming is a bit confusing, by “classic” I guess they mean “closer to the old vbulletin system”?
Here’s the non full-width discourse classic version. Jump doesn’t happen until about 4 seconds until the end around 2:30
Unlisted Youtube link
Sorry for the phone video. I can’t install screen capture software on my work laptop.
Haven’t had it happen in straight dope light yet.
Just happened with straight dope light. I didn’t get video this time, but I took a screenshot. You can see the back button where I got down to before it jumped.
Maybe this isn’t very widespread though? I would expect way more complaining. It gets super annoying.
It’s still happening to me exactly like the video you posted. I’m on Chrome on my desktop, scrolling with my mouse and using the Vincent theme. It seems to happen at least once per session. I’ve been noting where my cursor is and it’s not near the scrollbar. It’s usually within the post itself.
Lucky us!
Hmm. Good sleuthing. Thanks for the videos, this helps a lot. I wonder if it is based on the advertisements? Another possible source is arbitrary image embeds. Discourse is very sensitive to known post height – if you have a post that suddenly expands from 10px to 1000px (say, it loads an image but does not specify the proper image dimensions in advance) this causes severe problems for tracking topic position.
I was thinking of trying an ad block to test, but can really only do that on my personal laptop which I’m not using much this weekend.
Seems to be independent of using scroll wheel. I was deliberately dragging down the scroll bar on the right to avoid the problem and it happened anyway.
My take on this thread is that no one ever really got to the bottom of this. Here it is 4 years later and it happens to me a lot. I suspect that it happens to anyone reading a thread when someone else posts to it. The hypothesis would be easy to test for anyone who has a buddy who is also a member.
I seemed to solve the problem, at least for me, by installing ad blocking. I didn’t want to. I wanted to support the site with ads. But the issue was too aggravating.
It never happens to me, it may have when this thread was started but not recently. If I’m reading a post and someone else posts to it, the new post simply appears at the bottom.
I’m using Adblock Plus and made sure it’s active at the SDMB. It’s been that way for several years and I can’t say that it has made a difference. Using a Mac and Firefox, with Malwarebytes and Avast Premium.