TabContainer selects first tab (0) when current_tab == -1 and does not persist value of -1

[thygrrr]

Tested versions

• reproducible in 4.5-beta1

System information

Win11, Godot 4.5 beta

Issue description

A tab container configured to allow deselection of all tabs, and in conflict with the help text, starts with the first tab selected, rather than no tab selected, if current_tab is set to -1.

The in-editor representation works as expected once, but not across editor restarts.

I suspect this is a problem in serializing the value, reloading the editor will result in the value being set to 0 instead of -1.

Steps to reproduce

1. Open MRP.
2. observe: first tab is selected (should be not selected)
3. observe: current_tab is 0 (and shows "rever to default" arrow)
4. set current tab to -1
5. observe: all tabs deselected
6. run MRP.
7. observe: first tab is selected
8. repeat step 4
9. save and close scene or quit editor
10. reopen scene or project
11. observe 2 & 3 again

Expected output: (editor state analogous)

Actual output:

Minimal reproduction project (MRP)

MRP-tabcontainer.zip

[bs-mwoerner]

Looks like TabContainer uses a convention where the first tab added is automatically selected, setting current_tab to 0. Since -1 is the default value, it is not serialized and thus current_tab is never changed back to -1 even if that is what was set in the editor. If that's the case, then I suppose there's currently no way to persist a -1 value for the current_tab property of a TabContainer that has children...

[thygrrr]

The docs expressly state that -1 means no selection. It's also an important expected behaviour for me.

[bs-mwoerner]

I wasn't contradicting you. This is clearly not working as intended. It's a good issue. 👍

[CreatedBySeb]

Confirmed on stable v4.4.1.stable.official [49a5bc7b6]. The -1 is not being persisted, and even manually editing the file to add it does not allow it to be persisted. Attempting to set current_tab to -1 does not work if deselect_enabled is false, so clearly there are checks that allow for -1 in the case of deselection being enabled, it just isn't persisted which results in you not being able to start with no tab selected. Adding a script that trivially sets current_tab = -1 in _ready provides a workaround, and achieves the desired behaviour.

Godot v4.4.1.stable - macOS Sequoia (15.5.0) - Multi-window, 1 monitor - Metal (Forward+) - integrated Apple M1 (Apple7) - Apple M1 (8 threads)

[thygrrr]

I think I found the bug. I'll try to write a fix and tests.

[thygrrr]

I can never make a PR without at least 1 code style and 1 macro issue 🗡 ❤
Fixed, pending PR: #108255