I found the following comment in the r41242 webkit version of
WebKit/gtk/webkit/webkitwebview.cpp in the popup menu handler:
I'm looking into fooling it as-is (30 more minutes max ), but Bundyo could probably just patch webkit with most of his old placement code. This person probably punted because it's a little tricky if you're in a hurry. Let's face it, having scrolling, roving popup menus on a small screen is a high-class problem! Maybe Nokia has shared some of their tight-to-the-chest browser code in the latest SDK. But I bet there's something in the Android stuff. Anyway, I think these are the obvious main issues; their order is my best-guess as to their priority:

1. No menu item can be underneath the tap point
2. Neither the right or left edge can be off-screen because the menu only scrolls up and down
3. vertical_menu_exposure = vertical_menu_exposure_max with A and B still true
4. The menu's distance from the tap point is the minimum with A and B still true and C at max
5. And I think the menu has to grab the input focus, especially if the current tap point is not on the menu frame

And since things seem to be picking up, let's be optimistic and remove "Simple" from our comment titles. But knowing where I want to go with this I might have to start using clichés such as "Kitchen Sink" or "Swiss Army Knife" or "Left Nut."