So,
Chapter I
1. I hit D, for Rapid, Inferred method,
2. I pick one drafting line,
3. I pick second drafting line (parallel to the first),
4. Rapid decides I want to place angular dimesnion....
Chapter II
1. Rapid + Inferred,
2. First object,
3. Second object,
4. Place vertical dimension, but Rapid decides I need horizontal....
Chapter III
1. Rapid + Inferred,
2. Pick Hole as a first object,
3. Want to change the prefix,
4. Wait for popup menu,
5. Prefix menu is not there....
This prefix menu is very slippery, sometimes its there sometimes its gone.