Bug 125418 [Field Assist] - API - Should ContentProposalPopup be public?
In the initial release of the field assist API, the ContentProposalPopup is public. There's really no reason for this to be the case, as the popup is driven by the ContentProposalAdapter. The ContentProposalPopup should likely be made an inner type of the adapter.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
* 
	 * @return the time in milliseconds that will pass before a popup is
	 *         automatically opened
	 */
	public int getAutoActivationDelay() {
		return autoActivationDelay;
	}
	/**
	 * Set the delay, in milliseconds, used before autoactivation is triggered.
	 * 
	 * @param delay
	 *            the time in milliseconds that will pass before a popup is
	 *            automatically opened
	 */
	public void setAutoActivationDelay(int delay) {
		autoActivationDelay = delay;
	}
	/**
	 * Return the content adapter that can get or retrieve the text contents
	 * from the adapter's control. This method is used when a client, such as a
	 * content proposal listener, needs to update the control's contents
	 * manually.
	 * 
	 * @return the {@link IControlContentAdapter} which can update the control
	 *         text.
	 */
	public IControlContentAdapter getControlContentAdapter() {
		return controlContentAdapter;
	}
	/**