It appears that after initially creating a salary component and adding it to a salary structure, then any subsequent update to the abbreviation in the component definition is not reflected in the salary structure. The link is to a gif showing the problem.
http://pilgrimagepublications.com/downloads/Salary%20Component%20Abbreviation.gif
That is not a Link field. Link fields are updated automatically by the framework when you change them. As it is not a link field and the Salary Structure doc has a reference you will need to clear the Link field in the Salary Structure doctype and then select it one more time so that it will fetch the new changes.
This is useful when you want to keep a history of your transaction. It will keep it as it was in the past, unless un refresh it.
Thank you.