I don't know if it's the intent, as pressing the button releases the water sufficent for flushing now.
Many brands of toilet, if the buttons or levers are held down, will let more water by.

Unlike traditional toilets which continue the flush after one has released the depressed handle my Caravelle doesnt have that feel. That is, one can continue the flush as long as I hold down the button. Is that the intent?

• Caroma toilets