Steps to replicate:
1. Open VE/Source editor
2. Scroll the page
There is an error appearing in the console at this point: Uncaught TypeError: this.getSurface(...).setSurfacePadding is not a function
I noticed something else after this error surfaces which looks pretty serious, not sure whether it's relevant to this error. But mentioning it here just in case:
3. After step 2, make some changes after this error appears,
4. Go to Save Changes dialog,
5. Go to Diff panel by clicking on "Review your changes"
6. Click on "Save changes"
7. Now click on "Edit source", the source editor does not open.