How to see the call stack of the functions being called in a page
If you want to see the complete callstack of the functions being called, you should set up a debugging environment for doing so.
The quickest way to do is by downloading the Quickstart: Prebuilt Drupal Development Environment, which is a virtual machine copy of preconfigured ubuntu. The netbeans IDE is configured for debugging the Drupal code. It also has an display to look at the callstack at the bottom of the IDE, when in debug mode.

What all is included in it:

Support for Drupal 7 and Drupal 6
Ubuntu Linux, Apache, MySQL, APC, XDebug, IMAP, UploadProgress
Firefox (with developer plugins) and Chrome
Drush, drush make, and custom drush commands
Install scripts for: Apache Solr, Aegir, Hudson, and Oracle
Netbeans and Eclipse, configured with XDebug
XHProf and Webgrind profilers. Emails logged as files
cvs, subversion, git, bazaar


You can have a look at its dedicated youtube channel for helpful screencasts.