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I mean , the left side said FORCE STOP...................... the right side shows Disable which is faded out
MY FRIEND, your exchanged of info solved my problem.... I was looking for CALLUI and latter I found out it was called
InCallUI ( my mistake)....... I found it at APPS-ALL and I clicked on it and then CHECKed the SHOW NOTIFICATION option.
NOW I am getting the Calling bar everytime when I called this Xperia Z2... You are really a great HELP.... Cannot do it without you.. thank you so much.. Now I can go to sleeeeeeep !!!!!!!!
Not a problem.......glad i could help 
Before I got the help from the FORUM to solve this issue, I did e mail SONY TECH support team for a solution. Today I have their reply telling me to download the PC companion and going thru more than 15 steps etc etc running the risk of losing everything downloaded into the phone. I found it very hard to believe it . They could tell everyone to use the PC companion to solve every issue while this issue can be simply fixed by
SETTINGS, APPS---ALL.....InCallUI...... check mark Allow notification............
I hope all Z2 users will use the above method to solve this issue and not the PC Companion as given to me by the SONY support team.