POSX
Thumbnail position in the horizontal scrollbar in any unit.
Value
Any floating-point value. Must be a value between XMIN and XMAX-DX.
Default: "0.0"
Note
When the canvas is visible, a change in POSX generates a redraw in the horizontal scrollbar on the screen. This attribute does not generate a redraw of the canvas. Shall the user need this, he/she must call a redraw callback.