Syntax Highlighting flashing on idle

[Tragetaschen]

Describe the bug:
I'm not sure how I got where I am…
I have been editing in a single Razor file in VS and right now, I'm in a state where colors from syntax highlighting only appear for a very small fraction of a second before the text turns black again.

All background tasks are finished and according to Task Manager, VS is pretty close to being idle. However, there seems to be a constant 0.1MB/s IO happening

Version used:
VS2022 17.1.1

To reproduce:
shrug

Expected behavior:
Constant colors and syntax highlighting

Actual behavior:
No syntax highlighting most of the time with some very quick flashes of colorization

[Tragetaschen]

I have restarted VS and this file immediately shows the same behavior.
I noticed however that it depends on how far I scroll into the document. The following Gif shows changing between two scroll positions: One shows constant coloring and one "tick" further down in the document shows the quick flashes of color.
Scrolling up that one "tick" shows constant colors again.

All positions above that point are correct, all below are broken. The project fully compiles without errors.

I'm scrolling (down + up) twice:

[MartinThorsen]

Same issue as I was referring to in issue #6185

[NTaylorMullen]

@Tragetaschen / @MartinThorsen would you mind trying your scenario out in the latest VS 2022 preview build? One of our partner teams is saying they fixed this there: https://visualstudio.microsoft.com/vs/preview/

[Tragetaschen]

In VS 17.2.0 Preview 2.0 I have not been able to get into a no-syntax-highlighting state.

It's still a bit weird though: When I scroll through the document for the first time, with every wheel "tick" the syntax highlighting is lost and then restored. Once I have scrolled through the entire document, the highlighting is stable.

[MartinThorsen]

@NTaylorMullen I just installed the latest VS 2022 17.1.2 update and it is still not working correctly. Some types/keywords show up correctly, but some do. Scrolling like @Tragetaschen mentioned above seemed to work at first, but now I am right back to missing colors and the colors are still flashing.

In general, the editing experience is behaving very erratically when editing .razor files as opposed to .cs.

Ex: If I use the Ctrl-K, Ctrl-D command to fix my formatting, the document scrolls up and I lose my caret.
Ex: Sometimes using Alt-UpArrow to move a line works, sometimes it doesn't, sometimes it moves only part of the line.
Ex: IntelliSense is extremely slow.
Ex: Cursor and text cannot keep up with typing.

Also, it is as if the editing experience gets worse and worse the longer I am editing. I.e. the issues (and others) in the examples above get more and more prevalent.

[ryanbrandenburg]

We think the original issue is fixed. We think @Tragetaschen's secondary issue may also be fixed in the most recent builds, but we'll check it out locally and might get back ahold of you if we're not able to repro.

@MartinThorsen can you try out the experience in VS17.2 Preview2 and let us know if it reproduces? https://visualstudio.microsoft.com/vs/preview/

[MartinThorsen]

@ryanbrandenburg Man, I read that wrong. :-) I read that VS17.2 Preview2 was the second preview of an upcoming 17.1.2 release. I apologize. Installing Preview2 right now and will try it for a bit.

[MartinThorsen]

@ryanbrandenburg
I see the exact same issue as @Tragetaschen . When I scroll through the .razor file, the syntax coloring is lost and then restored. It will then stabilize once I have scrolled through the entire document. If I close and reopen the document, the behavior reappears. The coloring is lost and then restored.

As for the other issues I am seeing, I will let you know once I have used the editor more. Could be that the color flashing was impacting perf.