Currently, Painting is only possible when holding down the space button. There should additionally be support for a toggle, such that you can turn paint mode on and off. This particularly is useful when using a touch screen to paint, with a stylus. In addition, with laptops, default settings can sometimes be such that holding down space triggers palm-rejection, and disables the touchpad. This makes it impossible to hold down space at the same time as moving the mouse.
Currently, Painting is only possible when holding down the space button. There should additionally be support for a toggle, such that you can turn paint mode on and off. This particularly is useful when using a touch screen to paint, with a stylus. In addition, with laptops, default settings can sometimes be such that holding down space triggers palm-rejection, and disables the touchpad. This makes it impossible to hold down space at the same time as moving the mouse.