Can't move reference plans while editing a family

[mechitar]

I'm creating a window family by modifying a pre-existing one.  One of the things I need to do is to move the reference planes defining the "left" and "right" edges of the window opening, so as to make to opening wider, but I'm not allowed to do it.  The reference planes always move together, so that I'm stuck with a 3'-0" wide opening no matter what I do.  I can't find any constraints linking the reference planes to each other or to a 3'-0" dimension - I can't find any constraints on them at all, in fact.  What am I missing here?

The file in question is attached.  As I mentioned, the reference planes I'm concerned about are called "left" and "right".  I have been able to move other reference planes in the file.

[Alfredo_Medina · Accepted solution]

Look at the floor plan view:

[constantin.stroescu]

In Family Types > Dimensions > Width > Lock - uncheck it.

If you want the strech to be left -right of the Center ,then Modify >Pin it...

[constantin.stroescu]

It is recomanded  to make flexing from Family Type , as Alfredo says, instead of stretching it manualy as you try to do.....If you insist you can do it as suggested in my previous post, although is not usual and not advisable..