Mouse cursor going out of the game frame

[Briseris]

When being in B&S mode and perfoming skills, sometimes the mouse cursor accidentally goes out of the game window and then skills start not working anymore because the focus is on Windows' desktop elements ! 

Suggestion: it is annoying whenever it happens, maybe because the window mode is not forced(full frame on the screen) the problem occurs 

[Toodlepip]

I think the game is borderless windowed mode by default (even though it says 'Fullscreen' in the options menu). Try hitting 'Alt+Enter' a few times to put it in fullscreen mode, this might help.