The automatic spell checking is checking optional arguments to latex packages. For example in the lines

\documentclass[aps,reprint,prb,floatfix]{revtex4-1}
\usepackage[english]{babel}

the optional arguments in square brackets will be spell-checked. It seems that this is not the intended behavior.

Reproducible: Always

Steps to Reproduce:
1. Paste the two lines from above into a new document in kile
2. Enable automatic spell checking
3.
Actual Results:  
Optional arguments in square brackets are spell checked.

Expected Results:  
Optional arguments in square brackets should not be spell checked