2-finger scroll: I'm pretty sure this happens when there are no unscrolled bars under the cursor - so how about an old-school JS hack (remember those?): 1) put

2-finger scroll: I'm pretty sure this happens when there are no unscrolled bars under the cursor - so how about an old-school JS hack (remember those?): 1) put the annotation inside a container (and make that position:relative); annotation position:absolute, right:0px; 2) autoscroll the container 3) add some JS to infinitely increase the width of the container on a left-ish mouse move. (I think this will still work even if the container is, itself, in a cropping container. I suspect the result will be that 2-finger left swipe will be like quicksand - no apparent movement. Kind of sucks, but less than losing your page. An alternative would be to make history back/forward suck less: keep the display state in local storage and render a page just as it was the last time a person saw it (in terms of time display, modes, and selections). Probably that's a useful thing to do anyway and has Least Surprise in its side.