Where is _ab.p file located in OpenEdge installation ??

Unless you've downloaded the source from psdn, the only thing you'll see if _ab.r which is the compiled version of the file. This file lives in the <install>/gui directory.

Look here for the source to the AppBuilder and other tools.

http://www.psdn.com/library/kbcategory.jspa?categoryID=1660

probably, in the .pl files

there should be an extractpl script/batch file in the src dir

That works for some of the tools (dictionary, protools, etc.) but not for the AppBuilder. The only way to get that source code is to download the ADE sourcedcode (available for each version/service pack) from code-share.

The best way to compile this is using the pbuild script from the adebuild subdir. You need a cygwin or another windows like shell for windows to run the script.

I've reorganized code-share a "bit".

All development tools source code is located here: http://www.psdn.com/library/kbcategory.jspa?categoryID=1660

Excellent!