It seems like LG G4 has touchscreen related glitches. As per XDA's threads and posts, users of LG G4 have complained of facing issues with the touchscreen on the flagship smartphone.
For some users, LG's G4 smartphone rejected quick taps and swipes, effectively preventing the Knock On and Knock Code features to function properly. XDA developers conducted a poll to know about the number of G4 users who were facing the issue, and gathered that 60% of the users confirmed that they were facing this issue.
If you too own the LG G4, try these steps to check the performance of the touch screen:
- Open the dialer and type in 277634#*#
- Go to Device Test -> Service Menu - Manual Test -> Touch Draw Test - Manual
- Now Touch/ Tap/ knock/ Slide on the test area until it is full and watch out for the missing area where there will be no red mark on the phone if it fails to register a particular action.
Recapping the specifications, the LG G4 comes packed with a 5.5-inch display, Qualcomm Snapdragon 808 processor SoC, 3GB RAM, Android 5.1 Lollipop, a 16MP rear camera, a 8MP front camera, 32GB of internal memory, and a 3000mAh battery.