Tabs disappear on certain drag and drop targets under GTK

[tbiehn]

GTK Linux Builds - dragging a tab from a ghostty window to 'zed', or 'brave-browser' as a target makes the dragged tab disappear. Process associated with the tab stays active. The contributing window shows buggy behavior. For example, with a two tab window, you would expect a dragged tab would lead to two single tab windows without a visible tab bar. When dropping on zed the tab-bar remains with only a single tab in it.

Other targets, like dragging onto pcmanfm or sublime text, will create a new ghostty window with that tab.

Dragging and dropping between ghostty windows works as expected, moving a tab from one window to the next.

ghostty +version
Ghostty 1.0.2-main+1baf8928

Version
  - version: 1.0.2-main+1baf8928
  - channel: tip
Build Config
  - Zig version: 0.13.0
  - build mode : builtin.OptimizeMode.ReleaseFast
  - app runtime: apprt.Runtime.gtk
  - font engine: font.main.Backend.fontconfig_freetype
  - renderer   : renderer.OpenGL
  - libxev     : main.Backend.io_uring
  - desktop env: other
  - GTK version:
    build      : 4.16.7
    runtime    : 4.16.7
  - libadwaita : enabled
    build      : 1.6.2
    runtime    : 1.6.2
  - libX11     : enabled

[rhodes-b]

To give some more info, I tried this on a floating wm and could not replicate it, Kat was able to replicate also using a tiling wm

View discord thread for some more info
https://discord.com/channels/1005603569187160125/1323768827527434250

[mitchellh]

I suspect this is a GTK issue and not a Ghostty issue. I've been able to replicate this in the past and the behavior changes with GTK versions. That being said, if we can find a way to make it more stable I'd be happy to.

[tbiehn]

https://docs.gtk.org/gtk4/class.Notebook.html and src/apprt/gtk/notebook.zig for looking into it. Will spend some time looking at it.

[tbiehn]

@rhodes-b - are you on adwaita? I noticed that there's GTK Notebook and then there's Adwaita TabView.
when disabling adwaita: gtk-adwaita=false in config the behavior changes. The GTK notebook won't disappear into brave-browser or zed. They return back to the parent window. Dragging into pcman-fm yields a fresh window.
However, if you drag the same tab 10 or so times into zed or brave-browser it'll crash with this error:

debug(app): focus event focused=false
debug(app): focus event focused=true
**
Gdk:ERROR:../../../gdk/wayland/gdksurface-wayland.c:349:frame_callback: assertion failed: (!GDK_SURFACE_DESTROYED (surface))
Bail out! Gdk:ERROR:../../../gdk/wayland/gdksurface-wayland.c:349:frame_callback: assertion failed: (!GDK_SURFACE_DESTROYED (surface))
[1]    495794 IOT instruction  ghostty

[rhodes-b]

I was using adwaita, but I was also on x11

[tbiehn]

I don't really see many knobs to turn in order to change the behavior of Adwaita tabviews. GTK has some, but its behavior is also bugged up / I see nothing there that would cause inconsistent handling of tabs dragged and dropped onto different sorts of targets.

The last thing I was going to try was looking for https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/signal.TabView.close-page.html events, and seeing if we get close-pages for tabs that get orphaned - but can't get this event to log - maybe because the signature is wrong without a gpointer return. Regardless, this is probably a waste of time.

Seems like it might be reasonable to throw it on adwaita's issue tracker... other ideas?