SP - Windowed mode - Mouse jumping

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So, I notice that whenever I put my mouse on the bottom/right edge of the screen or when I open my inventory, it instantly jumps to like 2 cm to the left and 2 cm up.
I am playing SP, using 1.13c, windowed mode, Glide and PlugY.

I read in Glide3 settings info: "window-mode: If activated........ I recommend to use the "-w" parameter if you want to play in window-mode: the mouse then doesn't jump around if you open the inventory via keyboard".
I've tried disabling window-mode from glide3 and just put the parameter in the properties, but it had no effect(sent me to FullScreen).

Any ideas on how to fix that?

Thanks :)