A quick tip here for when a bluetooth mouse takes a moment to react after not being used for a few seconds. Bluetooth autosuspend can be disabled with a negligible power consumption penalty by setting a kernel parameter on boot.

1. Open /etc/default/grub for editing as root.
2. Find the line with GRUB_CMDLINE_LINUX_DEFAULT and append btusb.enable_autosuspend=0 to the end.
3. Save your changes.
4. Run:

   sudo update-grub
   

5. Reboot.

This solution was found here and is confirmed as a fix for Manjaro.