Boolean subtractons

[ENOCH ARYEE]

Hi all.
Here is a little mystery:
I want to drill multiple holes in a box primitive.
So I placed two or more little cylinders inside the box.
Next invoke (activate) the boolean subtract tool.
I click on one cylinder....then I click on the box.
Voila...the first hole is cut (punched out}. Beautiful.

Now the mystery.
I repeat the same operation on the same box, but this time, using the second cylinder.
A second hole is cut out, but..... the first hole closes.
I have tried over and over to get two holes..in the box, but no luck. The previous hole always closes. Only the last hole remains in the box.

I am using Cheetah 2.2. .... and loving it a lot.
I am sure there is a way of punching multiple round holes in a single square box...using boolean subtract
or other methods that I am not aware of.
Any suggestions will be greatly appreciated.

Thanks. Enoch