### Godot version

3.5.1mono

### System information

windows10

### Issue description

Error message
 scene/main/node.cpp:1362 - Index p_index = 0 is out of bounds (data.children.size() = 0).
 scene/main/node.cpp:397 - Parameter "p_child" is null.
 scene/gui/tab_container.cpp:593 - Index p_current = 0 is out of bounds (get_tab_count() = 0).
See "Steps to reproduce for details"

### Steps to reproduce

Set an external text editor
Create a script
Drop the script to the built-in text editor like this image:
![image](https://user-images.githubusercontent.com/119792950/209504041-039f2620-5e42-4c0f-8c41-cd24486fb3d2.png)
And got error message:
 scene/main/node.cpp:1362 - Index p_index = 0 is out of bounds (data.children.size() = 0).
 scene/main/node.cpp:397 - Parameter "p_child" is null.
 scene/gui/tab_container.cpp:593 - Index p_current = 0 is out of bounds (get_tab_count() = 0).

### Minimal reproduction project

An empty project
script_editor->ensure_select_current();
}
void ScriptEditorPlugin::save_external_data() {
	script_editor->save_all_scripts();
}
void ScriptEditorPlugin::apply_changes() {
	script_editor->apply_scripts();
}
void ScriptEditorPlugin::restore_global_state() {
}
void ScriptEditorPlugin::save_global_state() {
}
void ScriptEditorPlugin::set_window_layout(Ref<ConfigFile> p_layout) {
	script_editor->set_window_layout(p_layout);
}
void ScriptEditorPlugin::get_window_layout(Ref<ConfigFile> p_layout) {
	script_editor->get_window_layout(p_layout);
}
void ScriptEditorPlugin::get_breakpoints(List<String> *p_breakpoints) {
	script_editor->get_breakpoints(p_breakpoints);
}
void ScriptEditorPlugin::edited_scene_changed() {