Add mx_internal flag to RichEditableTextContainerManager to "hide" cursor so it doesn't intermittently show up in bitmaps. This may cause other bitmap compares to fail if the baselines captured the cursor. This should only be the case for Spark TextInput/TextArea/RichEditableText.
incubator/flex/sdk/branches/develop/frameworks/projects/spark/src/spark/components/supportClasses/RichEditableTextContainerManager.as