My version of Godot's Tab Container, but with keyboard functionality.
Includes a KeyboardBasedTabContainer class and control scene. It's supposed
to work more or less like Godot's own TabContainer: you add each tab's content
as a child Control node with the name you want to show up in the tab. Some styles
are exposed as editor variables so you can style the tabs in any way you want.
In its current version, the "ui_accept" and "ui_cancel" actions are used to enter and exit the tab's content (i.e. moving from the tabs to the content you added and vice-versa).
In order to work properly, each child Control you add must implement a
get_first_focusable_control method which takes no parameters and returns the
control you want to be focused when you enter the tab's content. This might
become optional when Godot 3.2.4 is released.
That's it, I think! I developed this for a personal project but figured it might be useful to others.