Split sysData.show() into separate show() and firstShow() to accomodate Windows's differing rules for first-time window show; this will also allow me to remove the error returns from sysData.show() and sysData.hide() (later).
More TODOs.
Removed error returns from Window.Show() and Window.Hide(). Also properly locked the Window's mutex lock in both functions.
Removed now-unused error returns from sysData.show() and sysData.hide().