Regarding collapse context

The help site from SAP is not clear on ...regarding "Collapse Context" node function..

In http://help.sap.com/saphelp_nw04/helpdata/en/58/cd834014d26f1de10000000a1550b0/content.htm

it mentioned CollapseContexts() as.....

Using collapseContexts() puts the first values of all contexts into a context. Empty contexts are replaced with an empty string

But actually when I used ...its taking the first value of each context ,Why so...

So is the documentation provided by SAP is wrong or I have taken it in wrong perspective...

Please suggest me on this....