P: When I am brushin on a mask, the option to switch between black and white stops working and I can only brush in or out.

I constantly use X to switch foreground and background color to quickly paint in masks. Suddenly there are buttons on the taskbar that regulate adding or substracting from mask. This is not workable in daily use. Ther is never a task that is only addding or only substracting. I use the colors, and not just black and white, also grey tints. 

This is not a helpful change.

same issue as OP

Photoshop version: Beta 28.0.1
Operating system: macOS 26.6.2
Brush settings: Normal mode, 100% opacity, 100% flow

When painting on a layer mask, the brush applies black regardless of the foreground and background colours. Even with white selected as the foreground colour, it still paints black.

Steps to reproduce:

1. Open a document with a layer mask.
2. Select the mask thumbnail in the Layers panel.
3. Select the Brush tool, with mode set to Normal, opacity at 100% and flow at 100%.
4. Set the foreground colour to white and paint on the mask.
5. Swap the foreground and background colours and try again.

Expected result: White should reveal the masked content, while black should hide it.

Actual result: The brush paints black on the mask regardless of the selected foreground colour.

Photoshop version: 28.0.1 20261014.m.3714 ae936ff, x64 (beta, PublicBeta)
Operating system: macOS 15.7.7
Hardware: Intel Mac, 16 GB RAM, Intel Iris Plus Graphics 655

Issue:
When switching between a layer's image thumbnail and its mask thumbnail, the foreground/background color state does not update correctly between color editing and grayscale mask editing.

During mask editing, color selection sometimes becomes unresponsive. I cannot select white or another grayscale value for painting on the mask.

Expected result:
Switching between layer content and its mask should update the color state correctly. I should be able to select white, black, or any intermediate gray value and paint on the mask using the Brush Tool.

Actual result:
The color state does not switch correctly, and sometimes I cannot change the painting color while the mask is selected.

Frequency:
The color-selection freeze occurs intermittently. I have not yet identified a reliable sequence that triggers it.

Workaround:
Switch to the Pencil Tool and change the color with that tool active. This allows me to change the color again.