get_virt_mouse_pos() can return dummy -1, -1 in some cases, for example
when mouse is not considered "in" the area. render() is called
immediately and sets the initial mouse position to -1, -1 when the first
tick happens.
When starting player and mouse is already on the window but not moved,
then move the mouse, the mouse_move handler thinks that the mouse moved
from -1, -1 to the current position, triggering showing even when the
amount moved is less than osc-minmousemove.
Fix this by not letting render() init mouse position if the position is
dummy -1.
nanahi
fc7f6e0208