Multiline text controls occasionally get corrupted on refresh

[Michael von Glasow]

I have recently updated from Ubuntu 12.04 (32-bit) to Ubuntu MATE 14.10 (64-bit).

After upgrading, I find that some text controls have a refresh issue that seems to get triggered either by scrolling or adding a new line when the text already contains more lines than can be displayed at a time. This happens infrequently and is not always reproducible.

The issue is that some lines in the text control show as blank lines. I have noticed this happen in the following applications:

* Eclipse 3.8
* Thunderbird (various versions)
* Firefox (various versions). In Firefox text is occasionally clipped, but not necessarily at line boundaries.

Other applications seem fine, it might be related to the widget toolkit (OTOH, the apps above use two different widget toolkits – Eclipse uses SWT while the other two use XUL).

I am also seeing a different kind of output corruption in Terminal, which may or may not be related. Similar to the above, it happens when I press ENTER while at the bottom of the terminal window.

I have seen the same issue on a second computer running a custom Linux build based on Kubuntu 12.04 (32-bit) with some components (including the kernel) being later versions than what is included in 12.04.

A third computer, also running Ubuntu MATE 14.10, does not seem to have this issue.

This seems to be a bug introduced into Ubuntu after 12.04, though I can't tell which component is at fault. It is possibly related to https://bugs.launchpad.net/ubuntu/+source/openjdk-7/+bug/1239607.

I will post more details (including screenshots) soon, so bear with me.

[Michael von Glasow (michael-vonglasow)]

Attached a second example with Firefox. Note the discoloration and the corrupted text in the first paragraph of item 10.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1418679/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Michael von Glasow (michael-vonglasow)]

Attached is another screenshot from Eclipse. This one happened after scrolling. The first four lines of the command_new function body are missing completely (the second line of that block is empty anyway, however), the fifth line is clipped. Also note the discoloration of the first two missing lines and the one preceding it.

[Michael von Glasow (michael-vonglasow)]

After taking the screenshot, the Save dialog obstructed the corrupt part of the window, and after the dialog disappeared the window was rendered correctly again. Anything that causes a re-render (obstruct and re-raise window, or select text) will restore proper rendering.

[penalvch (penalvch)]

Michael von Glasow, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal as it will automatically gather and attach updated debug information to this report:

apport-collect -p xorg 1418679

Please ensure you have xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

As well, given the information from the prior release is already available, testing a release prior to the development one would not be helpful.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Michael von Glasow (michael-vonglasow)]

It's still an issue on my system; I'll test the dev release and report here. Since it's a sporadic issue, please allow some time for testing.

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]

[Michael von Glasow (michael-vonglasow)]

Haven't tested the dev release yet but upgraded to Ubuntu MATE 15.04 since, and the issue is still there.

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]