"Yes" & "No" options not working in Tux paint app.

Expected behavior

After finishing our painting, we should be able to "Quit" or sometimes we accidentally click the "back" button and we should be able to "Continue" using these two features.

Actual behavior

Both these features does not work properly in this painting application.

How to reproduce

Launch the app.

Start painting.

After some time try to "Quit" or "Continue" using these two options "Yes,I'm done!
Or No,Take me back!

It doesn't work at all.

• Application: Tux paint.0.9.23-beta_1162
  Version 0.9.23-beta_1162

• Operating system:Android Naugat.
  Redmond 5a

Recording Of The Bug