Secret of Monkey Island - In full screen, when the mouse is moved to the edges and corners, it loses game focus. clicking will click the desktop. Don't move the mouse all the way to the edge. The cursor will change if you do which is a tell tale sign that is is going to click the desktop. alternatively use a gamepad.

Escape from Monkey Island - Herman Toothrot bug - Before you choose to interact with Herman save on another slot. According to other websites, "using" any item on Herman which is NOT a quest item in relation to Herman will trigger the game breaking bug. Just speak to him and carefully "use" the correct items. Don't randomly "use" items. I have encountered this bug but until i start a new game again, i can't verify this solution works.