Steps to reproduce:
- On an iPhone, start editing an article with mobile Safari in the WikiText editor (can be either logged in or logged out)
- Click the "Next" button
- Click in the text area to write an edit summary (which should activate the virtual keyboard).
- Hit "Done" to dismiss the virtual keyboard.
Expected result: You can now click "Save" and finish the edit.
Actual result: The "Save" button isn't visible and you can't scroll further up than the "How did you improve the page?" text. If you pinch to zoom out, however, you can get to the button and save.
Here's a screenshot. You can't scroll up further than this. Notice also the grey line near the bottom of the screen. Not sure if that's related.
Browser details: Mobile Safari, iOS 12.1, iPhone SE