As per discussion on dev mailing list (http://markmail.org/message/avn27zxog3giapvb):
We use <if-has-permission element for checking the specified permission of logged in party.
There are two supported attributes as well in which permission is mandatory and action is optional.
If action is not passed then it looks for specific permission.
It should be like <if-has-permission permission="LABEL_MANAGER" action="_VIEW"/>
Now if someone has LABEL_MANAGER_ADMIN permission, then that user won't be granted permission. It should check for _ADMIN permission as well.
This is properly handled when you pass action attribute, it checks for specific permission passed and _ADMIN permission as well.
We must use permission and action attributes at every such code occurrences to avoid this situation.