### Godot version

4.0 beta 10

### System information

Windows 11 Vulkan

### Issue description

Looked through the issues list, but couldn't find something like this, sorry in advance if this has already been reported.

There is a few cases (in the pictures below) where list of Actions in Input Map may not always show a scrollbar even if the actions list overflows (I imagine this could also happen for the widget that Input Map uses).

![image](https://user-images.githubusercontent.com/39958198/210003566-cf60dbaf-921f-485b-b0a9-51ffc28d0244.png)

![New Bitmap image](https://user-images.githubusercontent.com/39958198/210004079-8eb2e6a1-0cf5-4a7c-8905-a4e3cfd0ec5d.png)

![image](https://user-images.githubusercontent.com/39958198/210004165-a6b6790b-248a-4f68-b4d0-b44b25afdf4f.png)

![image](https://user-images.githubusercontent.com/39958198/210004537-aca52194-a464-48b9-b818-24782706de45.png)


### Steps to reproduce

The pictures are clearer than anything I could write here: "a picture is worth 1000 words"

### Minimal reproduction project

N/A
text_editor = memnew(LineEdit);
	popup_editor_vb->add_child(text_editor);
	text_editor->set_v_size_flags(SIZE_EXPAND_FILL);
	value_editor = memnew(HSlider);
	popup_editor_vb->add_child(value_editor);
	value_editor->set_v_size_flags(SIZE_EXPAND_FILL);
	value_editor->hide();
	h_scroll = memnew(HScrollBar);
	v_scroll = memnew(VScrollBar);
	add_child(h_scroll, false, INTERNAL_MODE_FRONT);
	add_child(v_scroll, false, INTERNAL_MODE_FRONT);
	range_click_timer = memnew(Timer);
	range_click_timer->connect("timeout", callable_mp(this, &Tree::_range_click_timeout));
	add_child(range_click_timer, false, INTERNAL_MODE_FRONT);
	h_scroll->connect("value_changed", callable_mp(this, &Tree::_scroll_moved));
	v_scroll->connect("value_changed", callable_mp(this, &Tree::_scroll_moved));
	text_editor->connect("text_submitted", callable_mp(this, &Tree::_text_editor_submit));
	popup_editor->connect("popup_hide", callable_mp(this, &Tree::_text_editor_modal_close));
	popup_menu->connect("id_pressed", callable_mp(this, &Tree::popup_select));
	value_editor->connect("value_changed", callable_mp(this, &Tree::value_editor_changed));
	set_notify_transform(true);
	set_mouse_filter(MOUSE_FILTER_STOP);
	set_clip_contents(true);
}
Tree::~Tree() {
	if (root) {
		memdelete(root);
	}
}