Tapping 7 times Build number in HTC Desire 300 does not work I am trying to enable developer options in my phone (HTC Desire 300) but tapping 7 times the build number doesn't work. Is there any idea? Thank you in advance!
Yes, starting from Android  4.2 the Developer Options menu are hidden by default. 

If your phone has any Android release between version 3.0 to 4.1, you don't need to enable Developer Options. Just access it by going to  Settings &rarr; Developer options.

Just to make sure you are doing it right, here are the steps: 


Launch Settings from the application launcher 
Select About Phone 
Scroll down and locate the Build Number entry
Tap on the entry 7 times. 
The Developer Options menu will now be listed under Settings again.