Cursor becoming invisible except at end of line

[austinbrian]

I'm having an issue in which the cursor in Jupyter notebook v5.1.0 (running in a Version 61.0.3163.100 Chrome browser) disappears while I'm typing. The cursor will usually show up at the end of a line, but disappears again when navigating, as you can see in a screen recording. The navigating actually happens, I just can't tell where the cursor is at any given moment, unless it navigates to the end of a line.

This seems like it is likely a CodeMirror issue, but I haven't found an example sufficiently close to debug.

[gnestor]

I unfortunately can't reproduce with notebook 5.1 and Chrome 61.0.3163.100 😕

Can you reproduce with a different browser? If not, do you have any Chrome extensions installed?

[DrNickBailey]

I'm getting this issue frequently on Chrome [Version 61.0.3163.100 (Official Build) (64-bit)]
I'm using the Stylish extension and disabling that seems to bring the cursor back.

[gnestor]

That explains it!

[rpep]

I've had the same problem, but I don't use that particular extension, so it seems that other Chrome extensions might interfere with this too in strange ways. Annoyingly, I can't identify what other extension I had that interfered, as after turning them all off, it fixed it, and now after re-enabling them all, the problem appears to be solved, but I'll keep an eye out.

[DrNickBailey]

Yes, I indeed noticed that sometimes the problem would be fixed after turning the extension back on, but then a while later the cursor would disappear. Sometime the disappearance is fleeting, and sometimes it will disappear in one tab but not in another. *Nick Bailey*Data Scientist * | Data Platform*+44 (0)1223 229 268

…

On 18 October 2017 at 13:28, Ryan Pepper ***@***.***> wrote: I've had the same problem, but I don't use that particular extension, so it seems that other Chrome extensions might interfere with this too in strange ways. Annoyingly, I can't identify what other extension I had that interfered, as after turning them all off, it fixed it, and now after re-enabling them all, the problem appears to be solved, but I'll keep an eye out. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#2909 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ALsKFKNBoO1qYET3JWGyoiqXrWKIt3kBks5ste8HgaJpZM4Pyvef> .

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[ian-r-rose]

We have also seen this problem in recent days with JupyterLab, also with Chrome 61 and MacOS 10.13. Cf. jupyterlab/jupyterlab#3097.

[gnestor]

@ian-r-rose Does it seem to be related to Chrome extensions?

[austinbrian]

Just wanted to chime in and say that I wasn't running Stylish, so I downloaded it, and running Jupyter notebook with one of the themes active actually did fix the problem at first, but after opening it again, I'm left with the same lack of a cursor. Disabling Stylish (and other chrome extensions) does not help.

Running jupyter notebook in Safari is perfectly fine though, so this may be a Chrome issue.

[rpep]

I disabled all Chrome Extensions on my machine, and I'm still getting the same problem after some time, so it seems maybe there's several problems presenting in the same way.

[Carreau]

I think I have seen similar things with OSX/Chrome on other websites, like piazza.

[gnestor]

@rpep @austinbrian @DrNickBailey Is it possible that the browser was zoomed in more than 100% when you encountered this? Apparently, this is a known bug on Chrome (1px borders disappearing on zoom). Could you also try to reproduce this in Chrome's Incognito Mode?

[rpep]

Yep, that seems to be the problem for me. I often work at 80%, and I can reproduce this now by altering the zoom level (doesn't seem to happen predictably though) and then clicking around in a box. Should say I'm on Ubuntu rather than OS X.

Edit: yes, can reproduce in incognito.

[jasongrout]

I was trying to find the relevant Chrome bug reports. There are search results for "1px border bug Chrome". Here's one fix that's already been merged: https://codereview.chromium.org/1412103005

@sccolbert may know of other references.

[DrNickBailey]

Yes indeed! I also work at 80%. Resetting the zoom returns the cursor. Now how to edit stylish to replicate the 80% zoom view... *Nick Bailey*Data Scientist * | Data Platform*+44 (0)1223 229 268

…

On 24 October 2017 at 17:26, Jason Grout ***@***.***> wrote: I was trying to find the relevant Chrome bug reports. There are search results for "1px border bug Chrome". Here's one fix that's already been merged: https://codereview.chromium.org/1412103005 @sccolbert <https://github.com/sccolbert> may know of other references. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2909 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ALsKFK1dmm4-FTlI1LhPrk0mSLQVUu6qks5svg-dgaJpZM4Pyvef> .

-- hivehome.com <http://www.hivehome.com> Hive | London | Cambridge | Houston | Toronto The information contained in or attached to this email is confidential and intended only for the use of the individual(s) to which it is addressed. It may contain information which is confidential and/or covered by legal professional or other privilege. The views expressed in this email are not necessarily the views of Centrica plc, and the company, its directors, officers or employees make no representation or accept any liability for their accuracy or completeness unless expressly stated to the contrary. Centrica Connected Home Limited (company no: 5782908), registered in England and Wales with its registered office at Millstream, Maidenhead Road, Windsor, Berkshire SL4 5GD.

[gnestor]

Great! You can try:

.CodeMirror {
    font-size: 1.2em;
}

This will just increase the font size of CodeMirror editors...

[willingc]

@gnestor Confirming that the cursor goes away when zooming to various levels below 100% on mac OS 10.12.6 and notebook 5.1.0. There are times when the cursor at the end of the line disappears and the cursor will not appear when clicking in the middle of already typed text.

A couple of screenshots. Let me know if you want me try anything in particular. Heading out but will do the next time that I am able.

P.S. Sorry I was doing this quickly on a notebook with RISE installed. The behavior was not seen before when I had 5.2.0. Not sure if coincidence or related.

[gnestor]

Thanks @willingc! Let me know if upgrading to notebook 5.2.0 resolves this (I don't think it will, but who knows!).

[blink1073]

I see the cursor disappearance on both 5.1 and 5.2.

[joydeep1701]

Seems like at certain values of zoom level, more specifically at 80%,67%,50% and sometimes even at 90% the cursor goes invisible. Setting zoom level to 100% brings the cursor back. Python 3.6.0 |Anaconda 4.3.1 (64-bit) Chromium Version 62.0.3202.62 (Official Build , running on Ubuntu 16.04 (64-bit)

[gnestor]

I was trying to find the relevant Chrome bug reports. There are search results for "1px border bug Chrome". Here's one fix that's already been merged: https://codereview.chromium.org/1412103005

What we can do now (until a Chrome bug fix is released) is change the border style for CodeMirror's cursor from 1px to 2px`:

.CodeMirror-cursor {
    border-left: 2px solid black;
}

That will make the cursor visible at all zoom levels, but it will also make the cursor twice as thick for zoom levels 67% and above.

[blink1073]

If I use 1.2px I get a 1px border between 50 and 110%.

[blink1073]

(no border below 50% and 2px above 110%)

[blink1073]

I see equivalent behavior on Firefox as well with that border width.

[gnestor]

With 1.2px I'm seeing the cursor until 25%, at which point it's visible on some lines and not on others. Switching to 3px at 25% brings the cursor back, so I was thinking that we could use CSS media queries to set the border conditionally based on viewport width (when zoomed to 25%, the width is ~3500 and when zoomed at 100% it's ~1000).

[blink1073]

I'm not sure there is a deterministic way to detect zoom level in CSS from what I can find on the interwebs.

[gnestor]

I'm going off of https://stackoverflow.com/a/22247258/2217533

[blink1073]

It looks like you can use that as a proxy, but not all devices have the same base width and you may or may not be full screen.

[gnestor]

Totally. This works for zoom levels 25%-200%, tested on a 13" MBP Retina:

.CodeMirror-cursor {
    border-left: 1.4px solid black;
}

// When zoomed out 67% and 33%
@media screen and (min-width: 2138px) and (max-width: 4319px)  {
    .CodeMirror-cursor {
        border-left: 2px solid black;
    }
}

// When zoomed out less than 33%
@media screen and (min-width: 4320px)  {
    .CodeMirror-cursor {
        border-left: 4px solid black;
    }
}

[blink1073]

The cutoffs are the same for me on a 15.6" MBP Retina.

[gnestor]

cutoffs = breakpoints?

[blink1073]

Yep

[louis-red]

Don't know if related, maybe a separate issue, but I also have a non-visible cursor

• in Jupyter Lab
• with Firefox Quantum 58 (could reproduce the issue with Chrome 64)
• only in the code editor (not in the notebooks)
• at all levels of zoom

[willingc]

Hi @JacquotLeHaricot, Thanks for the report. If you would like to follow-up with the JupyterLab development team, there is an open issue jupyterlab/jupyterlab#4104.
cc/ @jasongrout

[parthkhare]

Silly solution but try enlarging your screen size (Ctrl +), worked for me.