I'm using high resolution and the max zoom out. This is how to reproduce the bug: Load my savegame, go to your dungeon heart pressing "H" key, press TAB key to quit the left panel. The mid left screen will be black, ok, it seems like is because of haven't the panel but... if you move the screen to the left with the mouse, now the middle left screen appears. The more you go to the left side from the heart, the more the mid left part of the screen appears.
I don't know why this bug doesn't happen in the first level of DK original campaign, this is why I attach a savegame (is other level).