[Terminal] VT Mouse Support

[cerebrate]

• Your Windows build number: (Type ver at a Windows Command Prompt)

10.0.18890.1000

• What you're doing and what's happening: (Copy & paste specific commands and their output, or include screen shots)

I routinely use mouse mode in tmux with WSL for window selection, pane resizing, and scrollback, enabled in tmux.conf thus:

  # -- mouse support ---------------------------------------------------------                                                                                                                                                                                        
  # Enable mouse control (clickable windows, panes, resizable panes)                                                                
  set -g mouse on

While this works perfectly in conhost, it does not work at all in Terminal; nothing happens, as if the mouse events were never reaching tmux.

• What's wrong / what should be happening instead:

tmux mouse support (and presumably other mouse-supporting applications) should work as they do in conhost.

[zadjii-msft]

Yea, this is a known issue at the moment. We need to add support for mouse in two places: both in the terminal, to be able to synthesize mouse sequences, and in conpty to be able to read mouse sequences.

This issue is tracking the first bit, the Terminal functionality.

For the second bit, the conpty part, see #376.

[guibirow]

Sadly this does not work, having the mouse events with TMUX would defer the need to have multiple panes.
I hope this feature get implemented before the panes, is much needed and will solve most of issues

[jgkawell]

I would like to point out that the mouse support is also not supported in tmux within Docker (through Powershell). I know this is because the functionality simply isn't there in Terminal so of course it won't work in WSL or Docker, but thought I'd go ahead and mention it.

[guibirow]

the mouse does work with TMUX in WSL

[kumarharsh]

Mouse works with wsltty: https://github.com/mintty/wsltty

[jgkawell]

@guibirow Maybe it's an issue with Docker from within Terminal then.

[kumarharsh]

No. It's not an issue with Docker. It's an issue with conpty (this repo). Try wsltty if you want mouse support.

[jgkawell]

Are there plans to enable full mouse support in tmux for Docker in the future through Terminal?

[kumarharsh]

I don't know about Docker specifically, but i don't see why it should be any different than a normal terminal. This issue is about that, so keep an eye out!

[jgkawell]

So I just checked tmux through WSL 1 in Terminal and the mouse isn't supported there either. So my guess is that tmux itself just doesn't work in Terminal at this point and that it's not a Docker issue. Not sure what @guibirow was seeing on his end.

[guibirow]

You have to run a command to enable it, isn't enabled by default.
I don't have it right now, but it is simple like this set mouse on
I will have to confirm next week when I get my laptop

It only works on wsl terminal though, not in the new windows terminal

[jgkawell]

Oh I gotcha. Yeah it works fine in the plain WSL window. It only fails to work when embedded within the new Windows Terminal.

[egmontkob]

If you implement mouse support, please make sure to implement the SGR (1006) extension as well.

The legacy, byte-based protocol only allows row and column numbers up to 223, because 32 is added to this number and this is sent as a single byte. The column limit is not uncommon to be too small. (By the way, beginning at column 95 the generated data is not 7-bit clean and not valid UTF-8 which is a problem for encoding conversion layers such as luit.)

The SGR 1006 extension fixes these problems by encoding the numbers as decimal digits, and is supported by plenty of applications.

If this extension is not requested, please don't generate any event if the row or column exceeds 223. Otherwise an overflow could have nasty consequences. E.g. clicking on column 227 could generate the byte 32+227 = 259 = 3 = Ctrl+C which is typically the interrupt character sending a SIGINT to the running process.

[DHowett-MSFT]

So! Conhost actually does support DECSET 1006! Since we have this intervening layer (the pseudoconsole, which needs to talk to conhost), we get to choose what sort of mouse mode the pseudoconsole requests and supports. I see no reason that that shouldn't just be 1006 😄 Thanks for the info!

[DHowett-MSFT]

To clarify, because we have conhost in the middle, that would look like this:

                                      +-----------------+
                                      |                 |
                 DECSET 1002, 1005    | Windows conhost |
+-------------+                       |  (in PTY mode)  |
|             +----------------------->                 |
| Application |                       |                 |
|             <-----------------------+                 |
+-------------+                       |                 |
                 mouse information    |                 |
                 1002 in 1005 format  |                 |
                                      |                 |
                                      +---+---------^---+
                                          |         |
                                          |         | mouse information in
                         DECSET 1002,1006 |         | SGR Extended Format
                                          |         | (1002+1006)
                                          |         |
                                      +---v---------+---+
                                      |                 |
                                      | Windows         |
                                      |  Terminal       |
                                      |                 |
                                      |                 |
                                      |                 |
                                      |                 |
                                      +-----------------+

[egmontkob]

Did you mean 1005 between the application and conhost, or is that a typo in this picture? Mouse extensions 1005 and 1015 also exist but they are hardly used (if at all) due to their flaws, it's not something that applications are interested in.

1005 (xterm's two-byte UTF-8), 1015 (urxvt) and 1006 (xterm SGR), in this chronological order, are three mutually exclusive extensions to address the limitation of the column number. See e.g. Midnight Commander issues 2662 and 2956 for technical description about the flaws of the first two. Note that this story is now 6-8 years old. I'm not aware of any application that supports the problematic 1005 and/or 1015 but not the okay 1006. As such, I don't see any point in implementing support for the first two (although it should be very easy to implement them).

[zadjii-msft]

That very well could be a typo, right now, conhost actually supports a bunch of different mouse modes, including, but not limited to 1005 and 1006.

[giggio]

How do we copy the text when VT Mouse is enabled? I couldn't do it on Vim or Tmux.

[DHowett-MSFT]

Hold down shift to interact with the terminal itself instead of the application inside it.

[PetterS]

This is so great! When will we see a preview of this in the Store?

[DHowett-MSFT]

Stay tuned

[yveslange]

Downloaded from the shop! The mouse is working great in VIM, htop and Tmux. Finally, time to move from all other WSL Terminal to the microsoft one ! Good job guys and thanks a lot !

PS: shift is working great too !

[jsbarrett]

Just came here looking for why mouse wasn't working ... read the most recent comment from @yveslange and then updated the app ... and now mouse works perfect.

Thanks guys!

[nicolus]

@DHowett-MSFT : Mouse still doesn't work for me with Micro (https://github.com/zyedidia/micro), whereas both mouse and scrollwheel work flawlessly in the default powershell or cmd.exe terminal. Is mouse support only working in WSL for now ?

[zadjii-msft]

@nicolus indeed, mouse input only works for WSL applications currently. If you're using the Win32 version of micro, I'd bet that it won't work quite yet. You could probably work around this by running the WSL version for now. #376 is the issue we're using for the Windows mouse input

[CodeMonkey90]

@zadjii-msft
Mouse events don't work for me with a custom profile with "commandline": "ssh [...]". Is this also expected until #376 is resolved? Is there a good workaround?

Edit: Or is that just a result of PowerShell/Win32-OpenSSH#1310 and would work otherwise?

[DHowett-MSFT]

This is a result of PowerShell/Win32-OpenSSH#1310, which is (mercifully) fixed in the 8.x series.

[CodeMonkey90]

@DHowett-MSFT Thanks for the quick reply. In that case, is there a sane way to manually upgrade to a version with the fix right now or is it better to just wait?

[DHowett-MSFT]

Sure, just download the latest release from their Releases page!

[rfc805]

I don't see it here or in the documentation, but how do you turn this behavior off entirely? It's incredibly annoying for people who don't want to have mouse interactions pass through. Holding shift is not a good option.

[zadjii-msft]

@rfc805 there isn't a setting to disable this entirely - I'm not sure I've heard anyone request that before. Typically this is something that's controlled per-client application on other platforms, within the app's own config. Is there some app (vim, tmux, etc) in particular that's requesting mouse mode that you can't disable mouse input for?

[rfc805]

It's mostly vim (over ssh) but on a large variety of hosts which aren't related, which makes it non-trivial to globally disable in unlinked/unshared profiles across a few hundred different remote hosts. A lot of it involves copying data from those hosts across each other, or to other Windows apps, etc - so I find myself holding shift down my whole life if I use terminal instead of putty/mintty.

[zadjii-msft]

You know, this actually already is on the backlog. I'd go upvote #4875 ☺️

[paukul]

@rfc805 :set mouse-=a in vim will disable the mouse support for vim and should work around your issue until #4875 is merged

[rfc805]

Thanks - I do know how to do it each time, just overall a productivity killer if you work in a large environment with a profile you do not control.