Rendering issue in editor when keeping page up/down pressed

[WebsiteDeveloper]

Open the getting started content and open the index.html file,
then position your cursor in the first line and keep pressing page down
until the bottom of the file.

Result:
On top a part of the code is invisible

Expected:
Should work as scrolling down

Note: scrolling solves the issue.

[redmunds]

I've also hit this several times today on Windows 7, but I haven't been able to come up with a reliable recipe. The best recipe I can come up with is to open ProjectManager.js, press Ctrl-Home to start at the top, and hold down the PageDown key until you hit the EOF. My editor currently shows 48 lines (although I can see line number 49 next to the scroll bar) and the first 10 lines of the editor (and line numbers) are blank, so I can only see lines 1357-1394.

[peterflynn]

With @redmunds's recipe I can repro this fairly consistently. Sometimes the top chunk of lines will just flicker away for a second and then come back, but usually they stay invisible until you kick it by scrolling a little.

[peterflynn]

If I go back to just before the #2974 fix (git checkout 34f6412^ followed by git submodule update) this becomes much harder to reproduce. I still see the flicker occasionally, but I've never once gotten the missing lines to actually stick.

And if I go back even further, to before the #2810 fix (71d8957^), I don't even see the flicker.

So not surprisingly, mucking with page up / page down risks breaking rendering on page up / page down...

[pthiess]

Reviewed @jasonsanjose - please follow up on this one.
Thanks

[jasonsanjose]

@redmunds or @peterflynn I'm not seeing this today on win7 after the latest CodeMirror merge. Can either of you reproduce?

[redmunds]

I can no longer repro using my recipe from above on win7.

[WebsiteDeveloper]

i also can't reproduce this anymore so seems fixed

[jasonsanjose]

Closing. Thanks for confirming.