Thanks for quick reply. The problem is not so bad on a PC or Mac because the screen is already quite large. It is mainly a problem on phones because the screen is so small, so would be nice to view at full screen. A double click would also be so much quicker that having to right click - choose an app - then wait for it to open.
PS. After submitting this request, I realised the same option has already been requested by at least one person, KlausK. I did do a search on the forum for "Full" but it only listed 3 or 4 results in the first window, none of which were "Full Screen". However, when I did another search to look for my request, I found several more results. I think this is because I clicked return on the second occasion. It appears that when searching the forum, it only shows a few results until you click return. Perhaps that could be made clear when asking people to search the forum before submitting a request.