Blame Joyce Walker
Early versions of this webtext did not include a multi-windowed hypertexts category. Although I noticed the form, its implementation in early volumes of Kairos was to use individual windows to display linear texts, and I decided that it was linearity rather than multiple windows that defined those texts. Then Joyce Walker's "Hyper.Activity" appeared in issue 10.2. Her text uses three distinct windows that change simultaneously as you click through, and these multiple, changing windows are clearly part of the intellectual arc of the piece.
As a result, I decided that I had to add a multi-window category. I went back through the entire Kairos archive seeking out multi-windowedness, recounting and recalculating the percentages in my table. In all I found a total of five multi-windowed texts. Not a big difference, but I expect more of them to appear since fragmenting identity through multiple windows is a common aspect of how we use computers.