This task is now complete; its status should be changed from Outstanding to Completed. Posting the minutes spent on that.

I have the poem displayed on the left, with line-numbering; I have note anchors floating to the right of the poem, numbered; and I have the beginning of the apparatus showing on the right, with notes and note anchors linked. Before we go any further, it would be prudent to decide on a layout. These are some considerations:

• Ray's explained that it's important from the point of view of the publication that the apparatus be readable as a continuous flow of text, as it would be in a traditional edition (although in a traditional edition it would be broken across pages).
• From a usability point of view, that's a poor way to approach the design, because it's going to lead to multiple scrolling panes. Readers are likely to prefer to work within one scrolling page based on the text (as they do in a printed book), and access information from the other as they need to, by clicking on something.

So I have an idea. Imagine the poem and the apparatus appearing side-by-side, as if they're in columns on the page. Now, when you click on a note anchor in the text, the apparatus fades into the background (although it's still visible), and the content of the particular note you requested appears next to the point where you clicked, on top of the apparatus. If you click elsewhere in the faded apparatus, the popup note disappears, and the whole apparatus column is now clearly visible again. This is the scenario if you're reading the poem and referring to the apparatus.

Now imagine that you're reading the apparatus and referring to the poem. You click on a note in the apparatus. The poem text fades into the background, and a copy of the block (probably a line-group) which contains the note anchor now appears on the left, on top of the faded poem, next to the point in the apparatus where you clicked. Clicking on the faded poem dismisses the popup and brings it back to the foreground.

This solution allows for multiple reading approaches, and yet leaves both poem and apparatus on the screen for scanning or printing. I don't think it would be too difficult to achieve. What do you think?