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
void setContents(String newContents) {
				if (newContents == null) {
					newContents = EMPTY;
				}
				this.contents = newContents;
				if (text != null && !text.isDisposed()) {
					text.setText(contents);
				}
			}
			/*
			 * Return whether the popup has focus.
			 */
			boolean hasFocus() {
				if (text == null || text.isDisposed()) {
					return false;
				}
				return text.getShell().isFocusControl()
						|| text.isFocusControl();
			}
		}
		/*
		 * The listener installed on the target control.
		 */
		private Listener targetControlListener;
		/*
		 * The listener installed in order to close the popup.
		 */
		private PopupCloserListener popupCloser;
		/*
		 * The table used to show the list of proposals.