GT2710 - screen refresh

[KuBass11]

Hi All, and apologies for what is probably a proper newbie question.

I have a Mitsubishi GOT2000 (GT2710) connected via DH485 to an Allen Bradley SLC500. Most of it works fine except for one base screen, which when opened doesn't get updated with any values. Opening any overlaying window screen will then causes the underlying base screen to then get populated. It's almost as though the first screen doesn't know where to get it's data from until the second screen is opened.

As before I'm a beginner with this, so hopefully there is a simple setting that I haven't spotted.

Thanks in advance for any advice.