Edit -> Advanced -> Clean Whitespace doesn't

Edit -> Advanced -> Clean Whitespace doesn't seem to do anything anymore in my C/C++ files. I double-and triple-checked my whitespace settings in both C++ formatting options and Text Editor behavior. Both are set to tabs only, but clean whitespace still does nothing on simple leading-spaces code like:

    while ( TRUE ) 
    {

It is still reformatted and whitespace-cleaned as expected if it goes through a copy-paste cycle or drag-drop, so the formatting is working, it's just not hooked up to Edit -> Advanced -> Clean Whitespace somehow.