Bug 205923 [Viewers] Javadoc for setAllChecked() does not mention that only visible items are checked
setAllChecked which was added (by me) in 3.2 does not mention that all chidren must be visible for it to be checked (see setSubtreeChecked). We will have to leave it as it is API and does not expand the tree but I think we should deprecate it as setSubtreeChecked is really the only useful one. Boris what is your opinion?
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/CheckboxTreeViewer.java
* @param checked a writable set of elements (element type: <code>Object</code>) 
     * @param grayed a writable set of elements (element type: <code>Object</code>) 
     * @param widget the widget
     */
    private void gatherState(CustomHashtable checked, CustomHashtable grayed,
            Widget widget) {
        Item[] items = getChildren(widget);
        for (int i = 0; i < items.length; i++) {
            Item item = items[i];
            if (item instanceof TreeItem) {
                Object data = item.getData();
                if (data != null) {
                    TreeItem ti = (TreeItem) item;
                    if (ti.getChecked()) {
						checked.put(data, data);
					}
                    if (ti.getGrayed()) {
						grayed.put(data, data);
					}
                }
            }
            gatherState(checked, grayed, item);
        }
    }
    /* (non-Javadoc)
     * Method declared on ICheckable.
     */
    public boolean getChecked(Object element) {
        Widget widget = findItem(element);
        if (widget instanceof TreeItem) {