Option to not toggle foreground and background colours when showing / hiding mask overlay.

In fact you have three sets of FG and BG wells: one for the layer, one for the Mask (only works in B&W) and a third one for the overlay (also B&W), but by default to the latters two are inverted.

Hi, I notice a toggle of colors when the mask is selected and the \ key is hit, if the BG well is set to white, and the FG well to black when the mask is targeted. 

The buttons to switch FG and BG does switch colors. A FG/BG gradient in the option bar also switches direction.

Likewise, the FG and BG wells switch when targeting the layer or its mask, either by clicking or by their CTRL+2 or CTRL+\ shortcuts, if the FG is set to black and the BG to white for the layer.

Thanks Michael - that's good info and I should rephrase my question. 

I always have the mask targetted, but might start masking, then hit "/" to see the mask.  If I was masking black it swtiches to white. If I was masking white it stays white.  Can't the "/" function just be the same as on a layer where the foreground and background don't change?  I just want it to show the mask overlay, not mess with my choice of background and foreground colours.

When I have a layer targeted by clicking on its thumbnail within the Layers panel, tapping "\" has no effect on my foreground and background colours.

When I have a mask targeted by clicking on its thumbnail within the Layers panel, tapping "\" gives me a foreground colour of white and a background colour of black.

In neither situation am I seeing a swatching of colours. I am running Photoshop 23.4.2 on a Mac. I hope that helps.