SAPGUI option in connection string

I am using NCo 2.0.1

I have to setup my connection string.

For this I use the <b>destination object</b>.

I can't find any explanation about the three possible values for <b>SapGui option</b> in the destination object.

Three possible values are 0, 1, 2 what is the difference between them?

I also have a problem since Sapgui remains active (actually it is "frozen") in background even if i try to close it.

I have to force its termination.

Thanks in advance