You inserted a Border object with the Monogramming tool and found that it was not possible to change the width of the border, because the value box was greyed-out in the Object Properties dialog box.
You need to do a “Break Apart” for the Border object to be able to adjust its width:
You have inserted a border object with the Monogramming tool.
1) Right click on the object
2) In the right click menu, click on the “Break Apart” menu
Note: the Input C width value box now becomes active and you can adjust the width value.