pluma input lag (very slow)

[Jeffry Johnston]

pluma is extremely laggy, to the point of being borderline unusable. Each character takes approximately 1 second to appear after being typed (some faster, some slower).

Ubuntu MATE 18.04
CPU: Intel i7-8700K (99% idle)
RAM: 16GB (14GB free)
Keyboard: Lenovo USB keyboard (wired)
GPU: nVidia GTX 960, with proprietary driver

Version: pluma 1.20.1
Plugins: None enabled
Syntax highlighting: Plain text
File size: Happens with a new file (completely empty), i.e. File > New

Recreate:
1) Open pluma (don't open a file, just pluma)
2) Start typing

Additional info:
I didn't have this problem under 16.04, but I know there were major MATE changes since then (gtk2->3)

[Alexander Browne (elcste)]

Have you tried any other app that uses GtkSourceView like Gedit, Meld or Mousepad?

[Jeffry Johnston (ubuntu-kidsquid)]

Might have found it! Ran pluma on Ubuntu MATE live (18.04) and it didn't have the problem. So, I straced pluma to see what files were being loaded from my home directory and started methodically renaming things one at a time. Renaming ~/.fonts.conf seems to have done the trick for me. The contents of that file were:

<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
    <dir>/home/REDACTED/.Fontmatrix/Activated</dir>
</fontconfig>

I also renamed ~/.Fontmatrix for good measure.

Did some searching and it seems that fontmatrix was last available back in 14.04. I didn't have it installed anymore, but it seems like something I might have checked out once upon a time.

Anyhow, I hope this can get back to the developers and not silently closed. I saw a few other frustrated pluma users around the web!

[Jeffry Johnston (ubuntu-kidsquid)]

Never mind.. I guess it was just being nice for a minute there. Lag remains :(

[Jeffry Johnston (ubuntu-kidsquid)]

I do not use Gedit, Meld, or Mousepad.

[Alexander Browne (elcste)]

If you install one or more of them, you can see if the issue is with Pluma or the GtkSourceView library they all use.

[APolihron (apolitech)]

I don,t have this problem. I have a question : your 18.04 is a fresh install or a update from 16.04?

[Jeffry Johnston (ubuntu-kidsquid)]

The problem does not seem to happen in gedit, it's quite fast, although I greatly dislike that editor in general. MATE first captured my interest because they had retained the gtk2 version of gedit, which was renamed to pluma. At the time gedit had already started changing the UI and I had been keeping pinned versions of the old gedit package, which was no longer necessary with MATE.

This is a fresh install of 18.04, but I copied my home directory from my previous installation (which has been upgraded over the years, going back at least to 14.04). That's why I suspect something in my home directory is causing the problem.

[APolihron (apolitech)]

what if you delete and then reinstall Pluma? You have some old configs store in the .home dir that it's doing this.

[Jeffry Johnston (ubuntu-kidsquid)]

I installed pluma on a different machine (clean install) and it runs very fast. However, if I ssh -X to that machine and run pluma, I get the lag (other apps are fine, so it's not the connection).

[Martin Wimpress  (flexiondotorg)]

I can not reproduce this.

[Jeffry Johnston (ubuntu-kidsquid)]

It's definitely still happening, even with a clean install, but I stopped using Ubuntu (I'm running Debian now). For it to also happen in Debian it must be an upstream issue. Editing icon names in MATE and typing in Hexchat (IRC client) are also affected. It's an intermittent issue, so it may take a bit of typing to reproduce.

[Launchpad Janitor (janitor)]

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