Fix issue of add/remove a frame at a scene before all key frames of a layer. When you added or removed a frame at a scene before all key frames of a layer, frameline was not updated correctly. It seems nothing happened, but domview is updated. This changeset fix this issue by correcting logic for boundary case.

Attach the onchange callback to your config to make tri-state checkboxes work (from change.js)

To read the checked options just do:
  $("SELECT-YOUR-CONTAINER").find("a.checked");
  or if you used "multiple : on"
  YOUR_TREE.selected_arr