Thank you @Flohack for your reply.
I think that is not a problem of Ubuntu Touch. Unfortunately it is related to the touch screen of my Nexus 4. I installed a paint app on UB Ports and check my touch screen and found out the down part of the screen where the Call button is located does not work properly. To do a more investigation, I also installed the Official Rom 4.2.2 and did the same check and the problem exists.
Thank you.

Hi, I installed Ubuntu touch by running commands on the following link:
https://devices.ubports.com/#/mako
But now somethings are not working well, such as phone call. I cannot make a call because the Call button does not work!! I type the phone number and then when I press the Call button nothings happens. Any help appreciates.