Bug 125955 [Field Assist] - StringIndexOutOfBoundsException when backspacing out of a filter
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
((IContentProposalListener) listenerArray[i])
					.proposalAccepted(proposal);
	}
	/*
	 * Set the text content of the control to the specified text, setting the
	 * cursorPosition at the desired location within the new contents.
	 */
	private void setControlContent(String text, int cursorPosition) {
		if (isValid())
			controlContentAdapter.setControlContents(control, text,
					cursorPosition);
	}
	/*
	 * Insert the specified text into the control content, setting the
	 * cursorPosition at hte desired location within the new contents.
	 */
	private void insertControlContent(String text, int cursorPosition) {
		if (isValid())
			controlContentAdapter.insertControlContents(control, text,
					cursorPosition);
	}
	/*
	 * Check that the control and content adapter are valid.
	 */
	private boolean isValid() {
		return control != null && !control.isDisposed()
				&& controlContentAdapter != null;
	}
}