Issue #1136130 by pillarsdotnet: Reinstated WATCHDOG_* constants; using PHP equivalents caused issues on Windows.

Issue #634616 by effulgentsia, rfay, sun: Fixed Various problems due to AJAX binding to mousedown instead of click.

#995854 by rfay, effulgentsia, sun, merlinofchaos, Damien Tournoud, manimejia: Fixed #ajax doesn't work at all if a file element (or enctype => 'multipart/form-data')  is included in the form

- Patch #647228 by sun, katbailey, Rob Loach: links are needlessly unable to fully participate in D7 AJAX framework features.

- Patch #769226 by Owen Barton, sun, effulgentsia, alanburke, bleen18, mfer: optimize JS/CSS aggregation for front-end performance and DX.

- Patch #561858 by effulgentsia, sun, rfay, Nick_vh, merlinofchaos, katbailey, dereine, tstoeckler: drupal_add_js() and drupal_add_css() to work for AJAX requests too by adding lazy-load to AJAX framework.

- Patch #756762 by effulgentsia, fago, sun: AJAX should follow same rules for whether to call drupal_rebuild_form() as non-AJAX submissions.

- Patch #756762 by effulgentsia, fago, sun, rfay, pwolanin: AJAX should follow same rules for whether to call drupal_rebuild_form() as non-AJAX submissions.

- Patch #645800 by katbailey, effulgentsia, rfay: ajax_deliver() ignores #ajax['method'] and incorrectly forces 'replaceWith' for simple AJAX callbacks, D6->D7 regression.

- Patch #671184 by Scott Reynolds, sun, effulgentsia, yched, rfay, Pasqualle: AJAX form can submit inappropriately to system/ajax after failed validation.

- Patch #684846 by effulgentsia, rfay, quicksketch, aspilicious: AJAX triggered by non-submit element fails if any elements are validated.

- Patch #656782 by effulgentsia: critical bug: ajax_process_form() results in settings being returned for elements that aren't re-rendered as part of the AJAX request.

#595972 by katbailey, sun, TwoD, quicksketch, merlinofchaos, and dmitrig01: Allow AJAX settings command to extend Drupal.settings.

- Patch #599804 by effulgentsia, catch: unify page, AJAX 'path', and AJAX 'callback' callbacks. Oh my, this is the beginning of something big.

- Patch #601570 by effulgentsia: hook_exit() and other cleanup needs to happen for AJAX requests too.

- Patch #556438 by rfay, effulgentsia, sun | quicksketch, Rob Loach, Dries, sun.core, Damien Tournoud: Fixed AJAX/AHAH 'callback' support only works for 'submit' and 'button' elements - Should work for all triggering elements.

- Patch #551694 by effulgentsia, rfay, sun | moshe weitzman, Dries: standardized the return of status messages in AJAX callbacks.

- Patch #556018 by Damien Tournoud, dereine | sun: rename drupal_to_js() and drupal_json() for consistency and readability.