In high school, I used to tutor senior citizens to use computers at the town library. One thing that regularly tripped them up in the browser was the scroll bar. When they wanted to scroll down the page, their mental model of the page made them want to “pull the page up” to view the parts below. Thus, when they wanted to scroll down the page, they would press the up arrow. I’d never thought about scrolling this way, and I couldn’t really come up with a reason that their interpretation was wrong.

iPhone (and similar touch device) scrolling changes from the scrollbar model to the senior citizens’ model: now you flick up to go down the page, which feels intuitive, even for longtime scrollbar users.

The touchpad on macbooks has a gesture that denotes scrolling: dragging up or down with two fingers. Dragging down scrolls down the page (following the scrollbar, not touchsceen model). I use this a lot and really miss it when I’m on a non-mac touchscreen.

Today, the models converged in a funny way: I was reading through some blogs, and I scrolled down to a post that had a picture of the iphone browser interface. When I looked at the iPhone interface, my brain unconsciously switched scrolling models and I tried to scroll down by dragging my fingers up. Needless to say, I was quite confused for a moment.

For a while, I’d been having a problem where firefox would beach ball (aka hang) a lot on my mac. It wouldn’t be hitting the CPU, which seemed quite confusing. This behavior was much more pronounced when I was on a high-latency connection, like the ones on the shuttles to/from work. Sometimes, the problem wouldn’t happen at all.

Last night I finally decided to look into this, and found this bug: if you’re using a proxy configuration from a PAC URL, the browser hangs when it resolves DNS queries (it’s the result of some apple weirdness). So, my workaround is to not use the PAC file whenever possible (I only need it a few times a day). I guess this is only a workaround in a certain sense, but whatever. Since I made the change, I haven’t had any beach balls.

I’ve installed the switchproxy extension to make switching the proxy on and off really easy.