Empty hidden editors

[tsmaeder]

What it does

Monaco editors don't work correctly when they are hidden by setting display: none. This PR unsets the editor model from the editor when it is hidden and restores it when the editor is revealed again.

Fixes #14880

How to test

Test the scenario from the related issue. Have an eye out for an missing state in the editor or focus issues. This needs to be tested on Linux to make sure the issue is fixed as it did not happen on Windows.

Follow-ups

Breaking changes

• This PR introduces breaking changes and requires careful review. If yes, the breaking changes section in the changelog has been updated.

Attribution

Contributed on behalf of STMicroelectronics

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[tsmaeder]

@sdirix @msujew would be great if I could get some timely love for this one as it's the last one scheduled for the IDE patch release.

[sdirix]

This workaround fixes the main issue on my machine. However it seems to introduce other behavior changes.

See this video for changes between the latest Theia IDE and the Electron Example of this branch:

OpeningEditorsRegression.mp4

The current Theia IDE behavior is already not that great:

• The editors are opened on the correct line on first click, however the top overlay swallows the selected text. Still the editors are "almost" correct
• On second click the correct line is shown centered in the UI

On this branch:

• More often than not, the editor just opens on the last line of the file which is bad behavior
• The second click then works fine, centering the line in the UI

As this breaks just clicking on file results for me in the IDE, I would not recommend merging in this state. In both cases it would be better if the selected line would immediately be centered, just like on the second click.

[sdirix]

Edit: I tested the latest master and there the same last-line issue appears. So it's not a regression of this branch, but something else on master.

As the main issue is fixed, I'll approve

Edit2: Maybe it's a me issue 🤷, I went back several Theia versions on master and still encounter this issue when running the example apps.

[msujew]

I can confirm that this works as expected and does not introduce any regressions (I specifically checked the notebook integration as well, which simply behaves as usual).

[sdirix]

We somehow overlooked a massive regression to the chat view: The input grows infinitely.