I was playing about with FactoryPMI and put a slider control on the screen with its output tied to the text property of a Text field. The Minimum and Maximum Values of the slider were 0 and 360 respectively.
I noticed that things work fine when you use the mouse to move the slider. However, if you highlight the slider with the mouse and then move it with the left and right cursor keys, you are able to select -1 and 361. Also, if you use the Page Up and Page Down keys, the range increases to -36 to 396.
I don’t know if you are already aware of this?