Creates a top-level Swing JFrame for use by the input method. The intended behavior of this window is:
- it floats above all document windows and dialogs
- it and all components that it contains do not receive the focus
- it has lightweight decorations, such as a reduced drag region without title
However, the actual behavior with respect to these three items is platform dependent.
The title may or may not be displayed, depending on the actual type of window created.
If attachToInputContext is true, the new window will share the input context that corresponds to this input method context, so that events for components in the window are automatically dispatched to the input method. Also, when the window is opened using setVisible(true), the input context will prevent deactivate and activate calls to the input method that might otherwise be caused.
Input methods must call Window.dispose on the returned input method window when it is no longer needed.