Bug 256651 [FieldAssist] Wrong location calculation of proposal popup shell if content control is near bottom in the screen
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
openProposalPopup(false);
	}
	/**
	 * Close the proposal popup without accepting a proposal. This method
	 * returns immediately, and has no effect if the proposal popup was not
	 * open. This method is used by subclasses to explicitly close the popup
	 * based on additional logic.
	 * 
	 * @since 3.3
	 */
	protected void closeProposalPopup() {
		if (popup != null) {
			popup.close();
		}
	}
	/*
	 * A content proposal has been accepted. Update the control contents
	 * accordingly and notify any listeners.
	 * 
	 * @param proposal the accepted proposal
	 */
	private void proposalAccepted(IContentProposal proposal) {
		switch (proposalAcceptanceStyle) {
		case (PROPOSAL_REPLACE):
			setControlContent(proposal.getContent(), proposal
					.getCursorPosition());
			break;
		case (PROPOSAL_INSERT):
			insertControlContent(proposal.getContent(), proposal
					.getCursorPosition());