Ubuntu 18.04: Sometimes, Highlighting Code and Switching Window Removes Code from Mu

[akaloti]

• What you were trying to do: highlight code in the Mu editor and then switch window.
• What happened: I highlighted the code, switched window, and then when I look back at the Mu editor, I see that the code I had highlighted has disappeared. This happens regardless of whether I switch windows by clicking or with Alt+Tab. The bug does not always occur; it seems more likely to occur if any of the following happen, but it might be coincidence: a) I try to copy/paste code first, b) I only highlight a part of a line instead of entire series of lines, c) the window that I switch to is a terminal. I am able to replicate this bug repeatedly and have encountered it on multiple different days.
• Technical details like the version of Mu you're using, your OS version and
  other aspects of the context in which Mu was running: Mu 1.0.3, Ubuntu 18.04, Python 3.6.9.
• The related actions do not seem to appear in the log, i.e. highlighting code and switching window are not registered.

[carlosperate]

Thanks for the report @aaronistheman. Does the selected text get replaced by anything? Like a space or tab? Could you also try the latest alpha version to see if the problem is still persistent there? https://github.com/mu-editor/mu/releases/tag/1.1.0-alpha.2

I haven't been able to replicate in v1.0.3 macOS Mojave, so if there are other Ubuntu users that could try to replicate this it would be quite useful.

[abixadamj]

I can say - it is often in 1.03 version. I have this often. Linux Mint 19.3
I can reproduce this even in 1.1.0_alpha2. - rare, but it happens.
Video on my Vimeo: https://vimeo.com/442310555/c495c8172d

[carlosperate]

I can say - it is often in 1.03 version. I have this often. Linux Mint 19.3
I can reproduce this even in 1.1.0_alpha2. - rare, but it happens.
Video on my Vimeo: https://vimeo.com/442310555/c495c8172d

Thanks for the video @abixadamj, that's really useful to visualize the issue.
One off-topic thing, I wasn't aware the Ctrl+alt+i shortcut opened IDLE and I don't have the same in macOS. I had a quick look at the source code and I am not sure where that comes from? It was a very quick scan though, so I probably didn't search hard enough. Do you get this issue with alt-tab as well? Or just with this IDLE shortcut?

[abixadamj]

@carlosperate - ctrl+alt+i is my own shortcut to run IDLE. This issue is with alt-tab, because if I open IDLE with mouse (desktop icon) and then copy/alt+tab/paste - the same problem occurs (but sometimes, not every time).

[carlosperate]

This was also replicated by user @ajoh504 in gitter minimising the window in Ubuntu 20.04:

I'm using Mu on Ubuntu 20.04.1, and I've encountered a glitch where if I minimize Mu while all my code is still highlighted, it deletes all of the code. Has anyone encountered this problem?

I was able to replicate in an ubuntu 20.04 VM with v1.1.0-beta.5 by simply changing window focus.

text-deletion.mp4

It seems like it happens only once until the file is edited again. So if a text is selected, the window focus changed, that erases the text, but it doesn't happen again until the file is edited:

@ntoll can you replicate this on Debian?

[carlosperate]

Looks like this was an issue in QScintilla that will be fixed in the next release! 🎉
https://www.riverbankcomputing.com/pipermail/qscintilla/2022-April/001539.html