Incorrect focus behavior when Visibility == Visibility.COLLAPSE

[hannsl]

When a style's visibility is set to Visibility.COLLAPSE, the associated field paints and lays itself out correctly, but its focus behavior is incorrect. For example, in the case of a vertical field manager, the manager's subfields are no longer visible but they are focusable.

[hannsl]

In order to workaround the issue temporarily I added the following method to FieldDelegate

public static boolean isVisible(Field field) {
    return isVisible(getStyle(field));
}   

and overrode the isFocusable method in the manager implementations as

public boolean isFocusable() {
    return FieldDelegate.isVisible(this);
}

This workaround fixes the issue, but the next issue was that I received a lot of the following warnings in the console:
WARNING: Cannot layout field, insufficient height or width

In order to remove the warnings, I modified ManagerDelegate.sublayout as follows:

public static void sublayout(int maxWidth, int maxHeight, Manager manager) {
    if (manager instanceof GzManager) {
        GzManager gzManager = (GzManager) manager;
        if (!FieldDelegate.isVisible(manager)) {
            gzManager.gz_setExtent(0, 0);
            return;
        }

[infamous1982]

Touché. On it.