Is your site public? Can we get a look?
Installing and upgrading help
2.4 No Icons or Themes
As far as I can see, slasharguments is NOT turned off. Manipulating the links manually to look like it is off generates correct (looking) CSS.
You want $CFG->slasharguments=0 in your config.php btw.
Depending on your circumstances you may have to fight with your local web caches to actually see the change after you do that.