Eu também tive esse problema. Pode ser corrigido nas configurações do driver Synaptics. Veja este tópico para saber como corrigi-lo. Caso o tópico desapareça no futuro, aqui está o que funcionou para mim:
Under your mouse properties, click on the last tab "Device Settings". Click "Settings" to pull up the "Synaptics Properties" window. Select "Tapping" and you will see a Gear and a Question Mark on the right side. The Gear allows you to go into "Tapping Settings." If you have Tapping unchecked, you cannot access these settings, but they will still be in effect. This was what was keeping me from finding how to disable this. Click into this and you can either uncheck "Enable tapping zones" or change the very last drop down box (with Top Right Action) to "No Zone". Proceed to back out, uncheck Tapping again if you so desire, and compute annoyance free.