Got same problem on HP Mini 210 2001sa.
Looks like right button on clickpad is not being detected:
xinput list-props "SynPS/2 Synaptics TouchPad" | grep Capabilities
Still got jumpy 'left click + drag', but its soooo close to being fixed! Multitouch etc. all seems to work well.
Synaptics Capabilities (297): 1, 0, 0, 1, 1, 1, 1
(update) - As VideoRoy and ufuntoo pointed out that single button detection is probably correct. Instead, when button a is pressed, the driver uses the position of the finger to determine if a left/(middle)/right click took place.