Adding tabs in floating windows does not respect surface

[knoellle]

Describe the bug

The tab_add feature only works on the main surface.
This is because TabViewer::on_add does not know which surface the tab belongs to.

To Reproduce
Steps to reproduce the behavior:

1. run cargo run --example tab_add
2. Drag any tab to make it pop out into an floating egui window
3. Click on the + button next to the popped out tab
4. Instead of inside the window, the new tab is spawned in the first tree leaf of the main surface.

Expected behavior
The tab should be added to the floating window, but as far as I know, this is currently not possible to implement.

Screenshots

Additional context
Ideally the node indices would be unique across the whole DockState structure or TabViewer::on_add should be passed the surface index.

[Adanos020]

Nicely spotted, we'll look into it.
Glad to see someone is testing the release branches 😄

[Adanos020]

Fixed by #167

[knoellle]

Perfect, thanks for the quick response! ❤️
Now all I need is popping out to an actual window :D

[Adanos020]

That would be trickier but who knows, maybe someone eventually implements proper multi-viewport support for egui :)