Icon does not appear when using Markdown preview.

[RokeJulianLockhart]

To reproduce:

1. Create .MD file.
2. Invoke Control+Shift+V

If I instead use Ctrl+Shift+P to invoke the Command Menu and manually invoke the

Printing: Print

command, I see

TypeError: Cannot read properties of undefined (reading 'build')
    at m.<anonymous> (/home/RokeJulianLockhart/.vscode-insiders/extensions/pdconsec.vscode-print-0.11.18/dist/extension.js:2:1294617)
    at Generator.next (<anonymous>)
    at i (/home/RokeJulianLockhart/.vscode-insiders/extensions/pdconsec.vscode-print-0.11.18/dist/extension.js:2:1290301)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)

[PeterWone]

That's because you don't have an active editor. As clearly stated in the documentation, you can print

• the content of the active editor by using the toolbar icon
• the content of a file by using a context menu

Display of toolbar icons is decided by VS Code, not by extensions. Extensions declare an interest in language identifiers. When VS code makes an editor active, it assesses the language identifier for the content of the editor. Then it displays whatever icons have been contributed by extensions associated with that language identifier.

When you put the focus on a window contributed by VS Code's built-in Markdown preview extension, you don't have an active editor so no extension contributed icons are displayed.

This absence of an icon is not a bug. The unhandled exception is, I suppose.

If you want to be able to print from the built-in preview editor (which is a built-in extension and could proxy the icon) take it up with Matt Bierner. He's responsible for the built-in preview extension. You won't see it on his personal repositories because it's in a Microsoft repo.

[RokeJulianLockhart]

#283 (comment)

This absence of an icon is not a bug. The unhandled exception is, I suppose.

Yes, @PeterWone, I don't dispute this. I believe I have phrased this as an FR. Consequently, do you mean to imply that this is impossible to provide per VSCode's current extension architecture? If so, I'm happy to file an issue with VSCode itself. Alternatively, are FRs not accepted as issues in this repository? I'm happy to separate the BR regarding the exception and the FR regarding my desire for this functionality if that's assistive in triage.

If you want to be able to print from the built-in preview editor (which is a built-in extension and could proxy the icon) take it up with Matt Bierner. He's responsible for the built-in preview extension.

Regardless, I'll contact @mjbvz. Thanks for that. I'll file it formally as an issue at VSCode's public repository, considering that it's in-built by default into the editor.

[PeterWone]

Feature requests are certainly accepted.

I was in the middle of an explanation of why it can't be done when I noticed that these guys have done it! Most of the information in extension authoring docs and stack overflow says what I said earlier. But look at this

That blue icon remains visible when the preview pane is active (ie no active editor).

I will move this feature request to the correct place and investigate.

You should get a notification from github about where I moved it. Please raise future feature requests there. Also please remember to revise the review score you gave when the issue has been resolved.

[PeterWone]

Looks like they did it by registering an activity panel. That's not really a meaningful thing for Print to do but I could register one and hide it. That's a bit hacky but it might work.

Then I'd have to figure out how to determine the file being shown in the Markdown preview. This may not be possible, because it's not possible to listen to messages addressed to another extension, but I'll see what I can come up with. Right now I'm supposed to be working so I'll shelve this till this evening.

Although this is a fascinating technical problem, to be honest a better solution would be to turn off Print and Close in the Print extension settings, and just use the browser for preview. This has the huge advantage that you can put it on another monitor, and it exactly matches what will print. You don't get hot update in the browser preview but you can refresh the browser for an updated preview.

Hot update in browser preview is something I'm looking into. It's not trivial but I think I can probably do it using CRDP (Chrome remote debug protocol). If I get that to work it would also be possible to implement scroll synchronization like what the built-in preview does.

[RokeJulianLockhart]

#284 (comment)

@PeterWone, that's incredibly comprehensive. Tthat's significantly more than I expected a developer to even attempt on my behalf. My thanks.