Why isn't my settings button working?

[mtlqrx]

Settings button not working

Hello,
The settings button on my OnePlus One running Cyanogenmod is not opening the settings menu.
I tried touching and holding button.
Either way phone reverts to whatever screen I was on before swiping to open choices.
Also the phone and message button have disappeared from lower left of screen.
help??

 

[mtlqrx]

Found solution:
1. Open homescreen menu
2. Tap on upward arrow (madeup of 3 dots)
3. Tap on "Protected apps" (at the bottom of the list)
4. Draw a pattern and remember it (u'll be using this pattern for accessing Protected apps again)
5. Search for "Settings" in the list of apps that apper and uncheck the box next to it.
6. "Settings" app will reappear in the app drawer.