netinst.iso - a "learning experience"- Part (-1) Gparted Live

[Richard Owlett <rowlett@cloud85.net>]

[strange subject line to bind temporally but not logically 
related questions ;]

I've been experimenting with Linux install - varying options 
of various distributions.
I shrank the Windows partition with Gparted Live without 
problem.
Did an unknown number of installs letting installer "du 
jour" use free space as it chose.
Between installs - "deleted" current Linux partition and 
went on with next experimental install.

At one point an install created 2 partitions in the 
contiguous free space. Prior to the next experimental 
install I 'deleted' both partitions.

Using Gparted, I could not find a way to create ONE 
partition using all the space of the TWO now 'deleted' 
partitions.

Were my expectations flawed?
Should Gparted have be capable of that?
A general partitioning question - where would I find 
comparative definitions of
  [Primary, Extended, and Logical] partitions?

TIA