This is configurable in the settings. One press on the fob unlocks the drivers door, two presses unlocks all doors. If the car is locked and you only want in the boot a press and hold of the boot open button will pop open the boot, all other doors remain locked.I find i have to press the unlock button twice to get my boot to open. And the boot button or unlock again to open the boot after getting out of the car after a drive.
I don't know if there is a setting to unlock all doors when the driver's door is opened.
If I need in the boot after exiting the car I just hit the button in kick panel to unlock the boot.