[Fixed Bugs and Problems]
- Fixed a bug where rulers are still visible when selecting "OFF" in the Ruler window.
- Fixed a bug where after Undo or Redo a ruler can be moved even though it is inactive and app crashes after touch-up off the ruler.
- Fixed a bug where a ruler may become immovable after performing "Trim", "Invart Horizontal" or "Invert Vertical" of Canvas tool.