Flashing the window title (and the task bar) via FlashWindowEx has no effect

[UweKeim]

Environment

Windows build number: Microsoft Windows [Version 10.0.19042.685]
Windows Terminal version: 1.4.3243.0

Any other software? Any program that flashes the window title like e.g. my own tool to do so: https://github.com/UweKeim/console-flasher

Steps to reproduce

I'm trying to acchieve that when a program, that runs in a CMD instance inside Windows Terminal, does makes a call to the FlashConsoleEx Windows API call, the flashing of both the window title and the task bar icon of Windows Terminal does happen.

1. Open a new Terminal instance with a cmd tab (i.e. no PowerShell)
2. Run a program that flashes the window title (and also the task bar icon)

Expected behavior

The window title and the task bar icon of Windows Terminal flashes.

Actual behavior

The window title and the task bar icon of Windows Terminal does not flash.

Additional remarks

Try running a program that flashes the window title in a regular cmd.exe (i.e. not in Windows Terminal) to see a live example of the expected behaviour.

[zadjii-msft]

Ah, this is another one of those things that won't work in Windows Terminal because conpty is returning garbage for the result of GetConsoleWindow. (Another one of these is #2988). That's one of the APIs that we're trying to discourage users from using in the future, because it won't work cross-platform, and it won't work in remote scenarios (like ssh).

One of the things we are working on is a VT sequence version of this functionality. Have a look at #6700. I'm not sure it does taskbar flashing, per say, but we can set the "progress" state of the window. I'm gonna tag in @PankajBhojwani to see if he has any other thoughts on the matter.

[PankajBhojwani]

What zadjii-msft said! We do already have the infrastructure in place to flash the taskbar (#8215 added the ability to flash the taskbar when BEL is emitted) so adding a VT sequence for this should be straightforward I think

[DHowett]

We may want to avoid having our own VT sequence for stuff like this. The bell, or the ConEmu Progress API (OSC 9;4) should be sufficient and more expressive. 😄

Whether the window flashes is a user preference, and no application should be able to override that.

[DHowett]

(Closing as answered, but do feel free to continue the discussion!)

[UweKeim]

Trying to get my head around the (to me rather new) concept of "VT sequences" (short for "Virtual Terminal Sequences"), here are some resourcen about that topic.

• "Console Virtual Terminal Sequences" – Microsoft Docs
• "Using ANSI colour codes in .NET Core Console applications" – Random blog post about this topic

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Basic example:

Console.WriteLine("\u001b[31mHello World!\u001b[0m");

This code would set the color of the text to red through the escape sequence ESC[31m. (31 for red), prints "Hello World!" and then finally uses ESC[0m to reset the color.

As another example the following would position the cursor two lines up, by using the escape sequence ESC[2A.

Console.Write("\u001b[2A");

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For the Bell VT sequence (^G, as described in #8215) I did not get it to work with this:

Console.Write("\u001b[G");

and also not with this:

Console.Write("\a");

But probably the reason it is not yet working is that my version of Windows Terminal does not yet include #8215.

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I hope this helps others in the future, too.

[UweKeim]

One and a half year later, this still does not work, as #8215 still seems to be not included, not even in the Preview of Windows Terminal. Sad.

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Edit 1

It seems it is possible now by using e.g. this from a C# console application:

Console.Write("\a");

See this comment of mine for details.