You can now mouse over intervals and achievements to highlight them on the activity timeline chart. Click on an achievement or interval to zoom to it on the chart.
Note that this doesn’t work for some achievements. I am sorting that out. Also still need to make it work for touch devices.
How does one zoom back out to the entire activity? Intuitively I click on the achievement or interval summary a second time. Nix.
Curiously, the answer is clicking on one of the graphs, which isn’t intuitive for me.
Great! 
And it does work for me on the iPad by simply clicking on the achievement;-)
While the zoom-out works like it always does in i.icu, it would indeed be nice to have an advanced version of @Howie ‘s point: clicking on the achievement again could go back to the previous zoom/display state (not simply zooming out)…
Awesome! Love this, it was one of my top wish list items 
I really like the touch of being able to click to zoom in to the interval.
I added zoom toggle as you suggested. Tx.
This is awesome. Thank you. Great timing because I managed a new 60second power record on my last ride!
Great feature, can we have like a bold for the “selected” interval or a color?
Thank you!
When you zoom an interval it now gets a darker border. Bold didn’t stand out quite enough (IMO).
I’m not sure if it’s the right place to ask but… when I hover my house on the graph it makes some kind of subtle “rattling” noise. Even if I disable the sound of the tab on Firefox the sound stays and it’s the only website where I experience that, it looks not browser related but I am the only one to have it ?
I’m on Arch Linux, wayland, pipewire
Intervals.icu definitely doesn’t have any code to play sound in the browser. I have no idea where that is coming from.
