You only can see the chart when it is selected. At least in the 40% view. I have not tried it with only the map screen up.
You select MAP and INFO and toggle to charts and then select the chart you want and select View. If the airport you want to see the charts for is not the selected airport on the info window you first must dial in the airport you want to see the charts for.
For instance I have selected direct and selected my destination and then gone to the charts to look at the departure field diagram and the destination airport is in the info menu already. So you have to toggle in your present airport and then select CHARTS to see the charts for your departure location. Its not hard, just have to learn the sequence and what to do when.
You can make the charts larger and then scroll around to see the portion you want to see using the toggle knob. Don't know about the Low charts but I would guess they are working or looking at it.
I have used the charts for several approaches and the geo-reference is great. You know exactly where you are on the approach (as an aid of course) for the approach. I highly recommend you get them but if you use a MAC to download the charts and update it is a little cumbersome and time consuming to update. If getting vectors for the approach and you want to be using the map for orientation or to proceed to a fix that is not on the approach plate, you would have to have the map up and the chart would not be visible until you select charts again.
I'm not an expert at it for sure and there may be a lot better ways to use the system then what I have come up with so far. Sure others will have an input. I recommend them and hope this helps