This issue only seems to happen for me when I add a new layer, then change the layer blend mode. Many times the blend mode box is still highlighted after I change the mode. I can click in the blank area of the layer box and it will deselect all layers and get rid of the highlight on the layer blend mode box. This does not allow keyboard shortcuts to work. I can pointer select the brush and every time I click with the mouse to paint something PS will ding at me. It will paint the stroke though. If I try to use bracket keys to change brush size it will ding but NOT change brush size. Trying to select a different tool with a keyboard shortcut will only get me a ding, unless the same letter is also a menu shortcut such as "s" for Select or "v" for View. You might think that I've accidentally hit the Alt key to activate menu shortcuts, but no matter how many times I hit Alt, I can ONLY get menu shortcuts to work. At some point after clicking different tools, making brush strokes, and clicking other things the active tool will revert to the last used tool before the layer blend mode change (which is usually the Spot Heal tool) and all keyboard shortcuts will now work as they should. At least until the next time I change a layer blend mode and the whole process starts all over again. Even though this happens quite often, I haven't been able to figure out what I do that actually breaks the "ding" "ding" menu shortcut "ding" cycle. Any help would be greatly appreciated. This has been happening to me across multiple versions of PS
That is, to my knowledge, an old Windows bug not Photoshop. That bug can be productive some times but most of the time it is anoying. I can remember back to CS version to have same problem or bug on Windows only.