I have had to resort to using an old Photo Paint version X4 to press and hold the alt key when using a tool to get a straight path. I use this frequently and it disappeared after X5. I have X7, X8 and 2019 but it is no longer available. I am hoping someone can tell me if there is another way to get this feature in later versions of Photo Paint.
Have you tried using the Ctrl key to get purely horizontal/vertical movement?
Yes, Ctrl works for horizontal and vertical, but I need to use it for any direction. After X5 using the Alt key to create a stroke path in any direction disappeared.