private boolean isTickBox(final NativeEvent event) {
        boolean isTickBox = false;
        Element element = event.getEventTarget().cast();
        for (int i = 0; i < 4 && !isTickBox && element != null; i++) {
            final String className = element.getClassName();
            try {
                isTickBox = className != null && className.contains("tickBox");
            } catch (final RuntimeException e) {
                // Ignore.
            }
            element = element.getParentElement();
        }
        return isTickBox;
    }
Construct a new {@link CheckboxCell} that optionally controls selection.

@param dependsOnSelection true if the cell depends on the selection state
@param handlesSelection   true if the cell modifies the selection state
stroom-core-client-widget/src/main/java/stroom/cell/tickbox/client/TickBoxCell.java