--Issue Summary--

The title says it all

--Steps to reproduce--

Just open Pencil2D and tip several times on the canvas (around six times will trigger the issue): Pencil2D will open a window for "saving the animation" (?)
Close the window and repeat the steps again

--System Information--

• Pencil2D Version:
  Version used: Nightly Build Nov 7 2017

• Operating System:
  Windows 8.1

• RAM Size:

• Graphics Tablet:
  Huion tablet