Penumbra Overture highjacking mouse

[Jack1]

I'm playing Penumbra Overture in windowed mode when creating and testing maps and scripts. So the problem is this: whenever i start Penumbra it highjacks my mouse and i cant get it out of the game window without closing the game. Alt tab works sometimes but it makes the window go jerky. I thought of fixing this problem in the Overture source code but i couldnt find anything related to window and mouse handling. I want it to be like when i open the pause menu or any other menu in the game that shows the mouse cursor, i want to be able to move the cursor out of the game window. If someone from the developer team would assist me or someone that knows little better than i do i would appreciate it very much.