Autodesk Inventor

[#1]

When I start to constrain the sketch using vertical constraint, I was surprised to see that the end points get aligned but the line also got move out of position.  I may have accidentally set the Tools option but unable to figure out where the error is.

[#2]

You are missing other constraints.

Right click an select Show All Constraints.

Right click and Show Degrees of Freedom.

I recommend beginners sketch one line, circle, rectangle or polygon and dimension/constrain immediately before continuing. 

http://home.pct.edu/~jmather/skillsusa%20university.pdf

[#3]

Here is what I got after showing all constraints and dof.  Still not knowing where I have gone wrong.

[#4]

Might have been more instructive to attach the file, but -

looks like you are missing a whole bunch of coincident constraints.
Did you fool with Constraint Persistence or Constraint Options?

It looks like you have Constraint Persistence on now, but could you have turned it off earlier by mistake?

[#5]

You can have both buttons active, but if Constraint options are turned off, then you have overriden the constraints. RMB in the graphics area, and select Constraint options. Turn them all ON.  This link should help explain constraint settings:

Sketch persistence

http://teknigroup.com/courseware/2010/Module00/sk1/Videos/sk1-100/sk1-100.html

[#6 · Accepted solution]

Hi Dennis, that is exactly what I miss out and need and am glad to be able to get help so soon from here.  This is definitely accepted as solution and I like to thank the helper. 

However, if I click the accept as solution, I will not be able to show any appreciation.  I wonder if there is any opportunity for one to pen his words of kindness or upload the solution after accepting the solution.