Sometimes we will face below issues in R12.

Issue 1:
You have insufficient privileges for the current operation. Please contact your System Administrator.

You cannot run a page which is not Self Secured when the MAC fails.

Resolution:
 
Set the below 3 profiles to None
1) FND Function Validation Level
2) FND Validation Level
3) Framework Validation Level
JDev-2
Issue 2:
Unexpected URL parameters have been detected and will be ignored Solution:
 
Resolution:

In JDeveloper, go to menu Tools–>Embedded OC4J Server Preferences–>Global–>Startup–>Select Default Local IP Address.
JDev-3
 
 
To Access OAF Personalization in Oracle Apps, we need to set the values of following profiles options to enable Personalization Page link in OAF Pages. You can enable these profile options at all levels (Function, Site, Responsibility, User)


These four profile options are mandatory for working on OAF personalization in apps. To Assign these Profile Options, we need to go to System Administrator or Functional Administrator Responsibility.

Navigation:
System Administrator -> Profile -> System
Functional Administrator -> Core Services -> Profiles

Profile Name
Profile Value
FND: Diagnostics
Yes
Personalize Self-Service Defn
Yes
FND: Personalization Region Link Enabled
Yes / Minimal
Disable Self-Service Personal
No

Meanings:

1. FND: Diagnostics
Setting the FND: Diagnostics (FND_DIAGNOSTICS) profile option to “Yes” will enable the diagnostics global button to be rendered on the screen.

2. Personalize Self-Service Defn
Set the value to Yes to allow ‘Personalize’ link to appear at the right top of the OAF page.

3. FND: Personalization Region Link Enabled
It renders the “Personalize  Region” links above each  region in a page. Each link  takes you first to the Choose Personalization Context page, then to the Page Hierarchy Personalization page with focus on the region node from which  you selected the “Personalize  Region” link.

Two Options
Set the value to Yes to display all the personalization links above each OAF page region.
Set the value to Minimal to display key regional links.

4. Disable Self-Service Personal
Set the value to No will enable all OAF personalizations on all pages at all levels (Function, Site, Responsibility, User)


This article will explain how to add a DFF to a existing OAF page through personalization.I am using Supplier Quick Update Page ( /oracle/apps/pos/supplier/webui/SuppSummPG ).
If you want to see how to create DFF please click here.
In this scenario I am using a custom DFF. Following are the details.
Application -> Payables ( Code: SQLAP )
Name -> XXCUST_SUPPLIER_DFF
Title -> XXCUST – Supplier DFF
Table Name -> AP_SUPPLIERS
DFV View name -> XXCUST_SUPPLIER_DFV
Reference Fields -> ATTRIBUTE_CATEGORY
Following are the Context Field Details.
Prompt -> Supplier Type
Value Set -> XXCUST_SUP_TYPE ( Values : External and Internal )
Reference Field -> ATTRIBUTE_CATEGORY
Below table shows the segment details of XXCUST_SUPPLIER_DFF.
Code
Segments
Column
Value Set
Global Data Elements
Identification Number
ATTRIBUTE1
15 Characters
External
Type
ATTRIBUTE2
XXCUST_EXT_SUP_TYPE
Values
         Domestic 
          International
Internal
Department
ATTRIBUTE2
15 Characters
Following steps you need to perform to create flex item in the Quick Update page.
1) Click on Personalize Page.In the Personalize Page click on Complete View.
2) Click on Create Item.( Based on where you want to place the DFF choose appropriate layout).
3) Create flex item with following details.
4) If you want to arrange the item in the page click on Reorder.
Following is the output.