Yes, as I mentioned, I have the same xpath in use on a data grid form, which is working perfectly. However I would like to use the check box selector, rather than a data grid form.
Ok, I think I have found the issue. So, it does now seem to be working however there is different behaviour in the check box than in the data grid.
My Xpath was checking for selectable items existing in a relationship. When the relationship was set to a null/empty list, the check box seemed to ignore the Xpath, where the grid correctly saw the relationship as null. So, instead of setting the relationship to the empty list, I check for empty, then set the relationship to empty. I am not at all sure why this is any different, but it appears to be working now. ?
Sorry Chris, the last part is not accurate. The Checkbox does not seem to recognise the Xpath constraint where it is a relationship that is empty. SO instead of showing no items, it is showing all the items. So this is what the ' bug' is.