Recently the Dismiss Charm feat was added to level 1 Bard, Wizard, and Sorcerer, so they can cancel a control spell on a monster (when you want to kill it). Since those arcane classes make the most use of charm/dominate effects, it's understandable that other classes wouldn't have been burdened with the complexity of having an icon that they can't usually use.
However, there are reasons any character could charm a monster, and thus want to dismiss it:
* Ranger animal empathy
* Cleric/FVS Symbol of Persuasion
* FVS Command Undead
* UMD + Charm/Dominate scroll
* Wolf Whistle necklace
So, the suggestion: Give a dialog option to some magician NPC where for a fee of 100 gp, he teaches you Dismiss Charm
That way new players aren't confused by seeing that feat icon, unless they went out trying to get it.