The sluggishness that was previously an issue on Android devices is pretty much solved now.
In general it's a good idea to have the charts for neighbouring countries installed if you fly anywhere near the border. I think this example (Geneva) is almost certainly the most serious as the airspace extends 20nm into French territory.
Unfortunately there isn't a great answer to this. Although the French AIP does publish information on the Swiss airspace, we have found that it is often out of date and therefore inaccurate. The Swiss AIP is the official source of such airspace, but we do not refer to the Swiss AIP when creating our French chart.
It may be that a perfect solution will present itself at some point, but for the moment it's definitely best to have charts for neighbouring countries installed if you're flying within 20nm of the border.