Recently a friend brought me a Acer Aspire Laptop to install LMDE. Just started by the LiveCD I realized that with him touchpad could move the mouse cursor, but could not execute anything by clicking the touchpad.
Between the known issues de LMDE this is one of those that we can find, especially in the variant with Xfce and luckily, they provide us with the solution for it. To activate the «Click on tap» at touchpad we execute in the console:
sudo gedit /usr/share/X11/xorg.conf.d/50-synaptics.conf
and we replace the content of that file, but this other:
Section "InputClass" Identifier "touchpad catchall" Driver "synaptics" MatchIsTouchpad "on" Option "TapButton1" "1" Option "VertEdgeScroll" "1" EndSection
We restart the graphical interface (it should work by exiting the session and re-entering) and the Click on it should work. touchpad.