HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

I have a question. I like to play in 800*600 resolution in windowed mode, but often when I click on the map with the mouse, I accidentally click on the game itself and shift it by a millimeter. This causes the graphics to become blurry. Is there a way to fix it so that the window doesn't move? By the way, my tactics are fine. It's just that I had an old version of the game.