Não sei porque a GUI do Synaptics Driver não mostra uma opção, mas é capaz de fazer o que queremos. Confira as etapas abaixo, tiradas de link
No entanto, não segui o passo 3 e funciona mesmo assim. Eu tenho o Windows 7 SP1 e o Synaptics 7.5
- Press Win+R keys to open run, type regedit and hit enter to open Registry Editor.
- Go to "HKEY_CURRENT_USER\Software\Synaptics\SynTP\TouchPadPS2". If you don't find "TouchPadPS2" and another entry named "TouchPadSMB2c" exists under SynTP then click on "TouchPadSMB2c". If you don't find "SynTP" key then read note(*) at end of the post.
- On the right double click on "MultiFingerTapFlags" entry and update its value to 3.
- On the right double click on "2FingerTapAction" entry and update its value to 2.
- Press OK and Exit.
- Log Off and start Windows.
(*) If you don't find any of the above key then you have to manually create it. Right Click on Synaptics click on New Key and Give it name ""SynTP". Now similarly create a key named "TouchPadPS2" under "SynTP". Now under "TouchPadPS2" create new "DWORD (32 bit) Value" with name "2FingerTapAction". Double Click it and Change its Value to 2. Logoff and Start Windows.