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
String content = getControlContentAdapter().getControlContents(getControl());
		for (int i=0; i<autoActivateString.length(); i++) {
			if (content.indexOf(autoActivateString.charAt(i)) >= 0)
				return true;
		}
		return false;
	}
	
	/*
	 * Return whether this adapter is configured for autoactivation, by
	 * specific characters or by any characters.
	 */
	private boolean allowsAutoActivate() {
		return (autoActivateString != null && autoActivateString.length() > 0) 
		  || (autoActivateString == null && triggerKeyStroke == null);    
	}
	
	/**
	 * Sets focus to the proposal popup.  If the proposal popup is not opened,
	 * this method is ignored.  If the secondary popup has focus, focus is returned
	 * to the main proposalpopup.
	 * 
	 * @since 3.6
	 */
	public void setProposalPopupFocus() {
		if (isValid() && popup != null)
			popup.getShell().setFocus();
	}
}