Window doesn't take mouse input until it reenters window

[GeeTransit]

If the game opens under the mouse, mouse action's aren't detected until the mouse exits and reenters the window. Toggling fullscreen does not fix this.

[GeeTransit]

The new mouse mode toggle (M key) also needs the mouse to exit and reenter (using Alt+Tab) before GLFW_CURSOR_DISABLED works.

The mouse can be moved out, but is hidden when over the window. Clicking on another window moves the mouse to the top left corner of the original window. Clicking back now takes mouse input (with no limit on mouse movement).