Tested Ubuntu 17.10 beta 2 recently and that the touchpad ‘Tap to click’ feature does not work in my laptop while I’m in the GDM login screen, even though it starts working once logged in.
If you get the same problem and want to re-enable the ‘Tap to click’ feature in login screen before Canonical adding it back, following steps will tell you how.
You can enable ‘Tap to click’ either in Settings utility or via gsettings command. For working in the login screen, you need to do it under the gdm user.
1. Open terminal via Ctrl+Alt+T, then run command to get root privilege:
sudo -i
Type in your password (no visual feedback while typing) when it prompts and hit Enter.
2. (Not required in default Wayland session) Allow user gmd to create a connection to the X server:
xhost +SI:localuser:gdm
3. Switch to user gdm in the terminal:
su gdm -s /bin/bash
4. Finally enable ‘Tap to click’ via gdm user:
gsettings set org.gnome.desktop.peripherals.touchpad tap-to-click true
Restart your computer and done.
How to Restore:
To restore the setting, open terminal and re-do previous steps except running following command instead the last one:
gsettings set org.gnome.desktop.peripherals.touchpad tap-to-click false
