A visual indicator to understand how the screen viewports are currently split

The use case is to have a visual indicator on the viewports themselves denoting what split has been applied to the viewport., This is in case that there are no images in the viewports or the viewports are blank but a split has still been applied. Although this functionality would be applicable for any modality it was raised specifically by a mammo reporter that appreciated this same functionality in SenoIris / ISI and it is not present in NBI.

Although it is appreciated that the navigator can display the screen split applied at a visual level when thumbnails are moved in the navigator by the mouse movement, and obviously the screen split is apparent when images are loaded, this request is regards when image viewports remain blank - for whatever reason.

Additionally, where there are blank viewports, we would like to see some textual information e.g. "No images loaded" so users are not simply presented with a blank screen.

An example of how this would be visualized is provided in a mockup screen shot attached.