When a record is modified in a gridpanel, ExtJS is automatically adding the smal red tags to indicate that the record has been modified by the user. This is sometimes very annoying and you can get rid of them very easy by modifying the viewConfig of your gridpanel class.
How to do it
In the grid class you add the markDirty parameter to your initComponent function of your gridpanel class:
markDirty : false
/* .. more config .. */