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
*         keyStroke value is <code>null</code>, then all alphanumeric
	 *         characters will auto-activate content proposal.
	 */
	public char[] getAutoActivationCharacters() {
		if (autoActivateString == null)
			return null;
		return autoActivateString.toCharArray();
	}
	/**
	 * Set the array of characters that will trigger autoactivation of the
	 * popup.
	 * 
	 * @param autoActivationCharacters
	 *            An array of characters that trigger auto-activation of content
	 *            proposal. If specified, these characters will trigger
	 *            auto-activation of the proposal popup, regardless of whether
	 *            an explicit invocation keyStroke was specified. If this
	 *            parameter is <code>null</code>, then only a specified
	 *            keyStroke will invoke content proposal. If this parameter is
	 *            <code>null</code> and the keyStroke value is
	 *            <code>null</code>, then all alphanumeric characters will
	 *            auto-activate content proposal.
	 * 
	 */
	public void setAutoActivationCharacters(char[] autoActivationCharacters) {
		this.autoActivateString = new String(autoActivationCharacters);
	}
	/**
	 * Set the delay, in milliseconds, used before any autoactivation is
	 * triggered.