recommend setting for G3 is 1188x2112 dpi 528 which this setting you will not see any force close on LG app.(phone,gallery etc).
and this app also have power menu soft key for power off,reboot and reboot recovery your phone..
--- The option "apple default before power off" and "Re-apply setting after power on" is require for G3 lolipop with have Logo boot loop when change resolution.----
this option will track the phone power off and on for re-set and set back the resolution.
this app require phone rooted.... and require grant acces for super user
to avoid the boot loop in lollipop rom, please hit the "Default setting" every time before reboot phone by this app, will never get boot loop any more.
and when phone restart back i go to this app to set resolution again to safe battery.
on the latest update of this app have the check box name "apple default before power off"
you can check to enable this box to reset resolution to phone default when do power off or re-boot with the "power Menu" button on this app.
And the check box name "Re-apply setting after power on"
you can check to enable this box to apply new resolution when phone power on.
You can download this app from google play