Hi Neetu,
Did you already check the standard behaviour by setting the parameter WCF_IGNORE_ENHANCEMT = A in SU3 tcode?
I suggest you to check the standard behaviour first & please let us know the result,
Answers to your asked questions:
1.Is this normal flow, that while editing contact person, save button of account overview screen will be disable.
No, this is certainly not the normal flow, It might be possible this is project specific.
2. Where i can find the code which is getting enable and disable account to screen flow.
a) If you want to get the code behind Buttons, please check GET_BUTTONS of Tool bar.
b) To get the automatic SAVE logic (Project Specific), you can debug from BACK button of account overview itself.
Please let me know if you have any other concerns.
Best Regards,
Shakun.