Arbitrary scrolling (jumping) in clicks in modal UI for notebook

[fonnesbeck]

I am experiencing jumping behavior in the new modal UI for IPython notebook much more than I ever did in the original UI. Specifically, clicking into a large cell will arbitrarily scroll upward from the location where I click. I've prepared a movie that shows this behavior explicitly.

Running in Safari 7.0.1 on OS X 10.9.1 using IPython built from master 2 days ago.

[ellisonbg]

@fonnesbeck thanks for the report. I think this issue is caused by CodeMirror, but let's see if we can track it down. I think the issue is that when you click on an editor area, CodeMirror will focus the prompt. If the prompt is off screen the browser will scroll it into view. I have a feeling that the logic CodeMirror uses is to jump to the last position of the cursor. Can you play around with your example to see what happens if you first move the cursor to the bottom of the cell, then click away, scroll most of the cell above, then click back.

Also, to test this hypothesis, you can try clicking on the prompt area of the cell - it shouldn't jump. Then if you hit "enter" to enable edit mode, you should see the jump.

I will try to play around with this as well. But I have a feeling this will be tough to fix give the behavior is burried in CodeMirror and probably is the right thing to do (otherwise if you start typing it will be off screen).

[fonnesbeck]

In the movie, it does not scroll right up to the top (if "the prompt" is what I think it is).

[fonnesbeck]

Sometimes it scrolls upward, sometimes down. Happens a lot, though, and makes editing large cells pretty tough.

[fonnesbeck]

Here's another example where it scrolls up to the previous cursor location.

[ellisonbg]

@fonnesbeck I think I have fixed these issues in PR #4929 can you test and confirm the fix?

[fonnesbeck]

Based on testing with 2 arbitrary notebooks, it looks good. I will continue working from this PR for awhile and see if anything crops up.