JavaFX2.0 b44

So far, this bug only happens when using Microsoft PinYin input method engine, some other CCJK IMEs work fine with TextField. But Microsoft PinYin is the most popular and the default IME for Simplified Chinese Windows.
And this bug might be related to the classes in javafx.scene.input package.

Steps to reproduce:
1. create an app contains TextField or TextArea,
2. run the app on non-en Windows that Microsoft PinYin is installed,
3. invoke Microsoft PinYin, type relative long composing text, like "zhegeshijieconglaijiumeiyoutaipingguo".
4. press "Space" for a couple of times, until all composing text converted to Chinese characters and committed to the TextField.
5. press "BackSpace", until all committed text is deleted.
6. press any key to compose a new text.

StringIndexOutOfBoundsException reported:

java.lang.StringIndexOutOfBoundsException: String index out of range: 12
at java.lang.String.substring(String.java:1955)
at com.sun.javafx.sg.prism.NGText.getRangeShapeImpl(Unknown Source)
at com.sun.javafx.sg.prism.NGText.getRangeShape(Unknown Source)
at com.sun.javafx.tk.quantum.PrismTextHelper.getRangeShape(Unknown Source)
at javafx.scene.text.Text.impl_getRangeShape(Unknown Source)
at com.sun.javafx.scene.control.skin.TextFieldSkin.getCharacterBounds(Unknown Source)
at com.sun.javafx.scene.control.skin.TextInputControlSkin$6.getTextLocation(Unknown Source)
at javafx.scene.Scene$InputMethodRequestsDelegate.getTextLocation(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.getInputMethodCandidatePos(Unknown Source)
at com.sun.glass.ui.View.getInputMethodCandidatePos(Unknown Source)
at com.sun.glass.ui.View.notifyInputMethodCandidatePosRequest(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
at java.lang.Thread.run(Thread.java:722)


Snapshot video is attached.