OK this has happened twice now, but i will be 75% through Katzenstien's lab when my connection is lossed. The wierd thing is that it always happened a the same spot in the dungeon. Well my point is that it only ever happens here and I swear it annoys me to Hades. Has anyone else had a similar problem?
When you lose connection in the game (all of the clickable menus disappear), close the game window (click on the "x" in the upper right corner or use ALT+F4 if in full screen mode), open the game-launcher again, log in, and re-enter the game with your wizard. You should be back in business at the same location you were at, including if you were in battle.
You can also press ctrl + g to get the interfaces back if you are in battle. You will be able to see the cards but not the pips around your feet or the blades, traps, and shields on you and the enemy. After the battle you will not be able to move, but you can press the pgdn (page down key) in order to place a mark. Then press END. This will take you back to commons and restore your interfaces. Then you simply port back to your mark.