Pasted in yaml validation wrong

[alexyao2015]

When copy pasting yaml into the editor, the validator somehow still uses validation for the old yaml as if it was never updated. While the in browser editor will show invalid for the yaml, simply closing and reopening the dialog will show the yaml as being valid.

To reproduce:

1. Paste this yaml into the editor.
2. Close and reopen the editor.
3. Paste this yaml into the editor.
4. Observe validation errors.
5. Close and reopen editor.
6. Observe validation errors disappear.