Since we can't command+tab on fullscreen anymore, I've been using hearthstone on windowed mode for the past 3 months. Really used to it, running at 1920x1080. After Naxxramas patch there's a stupid bug that makes clicking things really annoying. Everything is like 2 inches away. For instance, if I want to click on "options", I gotta move down the cursor 2 inches, click the hearthstone board, then the option tab it will pop.
If I go back to fullscreen mode, that doesn't happen. In addition to that, if I try any other resolution on windowed mode, this issue doesn't appear.
Running the game on a late 2012 imac.