This may be an issue with other cards as well (I'm thinking Lookout is the other big one here but it came up for me in a game with Jack).
I play a Jack of All Trades, and let's say that before the Jack is played I had one card in my draw pile. I gain my silver and then now I'm looking at the top card of my deck. There's a window which shows me the top card of my deck, but while that window is up, my deck still displays that there is one card in it.
This is misleading, because that card is not on top of my deck, it's in my hand in being-looked-at-land. The display should show the number of cards that's actually on my deck at all times.