Process --> Apply Effect --> Gain -- > Invert channel phase
The "invert phase" control (under the 4 sliders) is without lettering,
and is not possible to see if it is checked or not.
In windows 7 you can see a light blue coloring - but in windows 10 it is invisible.
But there should also be a text near the controls.
This problem exist for a few years.
Obviously I'm the first who needs this feature.