A mouse event with so large numbers is discarded by Enigma
on purpose, because the black ball would suddenly be subjected
to an enormous impulse, if the mouse event would have been
interpreted the normal way. So, the ball not moving is a
logical and necessary consequence to an overly large mouse
xrel/yrel-pairing. So ... we have to ask: Why does SDL2 report
so large xrel/yrel-values?
I cannot reproduce the bug ... could you please answer the
following questions?
Do you use a special kind of mouse or mouse port?
Do you use an intermediary program (like a logger) or a
remote desktop? (Those might manipulate the mouse coordinates.
The fact that you observe the same problem using VirtualBox
can be explained by (1) VirtualBox manipulating the mouse
coordinates or (2) the host OS being involved in the bug.)
Were there other windows on the screen, besides Enigma's
window?
There is a bug report about SDL 2 here concerning "jumpy"
relative mouse motion:
It needs other windows other than Enigma to be present. It
should be closed on X11, but your host OS might still be
reporting wrong numbers. However, the numbers you report are
so much larger, that it just doesn't make sense, unless you
use something like a 40.000 x 20.000 pixel display?
Best
Andreas