### 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
ClassDB::bind_method(D_METHOD("set_custom_font", "column", "font"), &TreeItem::set_custom_font);
	ClassDB::bind_method(D_METHOD("get_custom_font", "column"), &TreeItem::get_custom_font);
	ClassDB::bind_method(D_METHOD("set_custom_font_size", "column", "font_size"), &TreeItem::set_custom_font_size);
	ClassDB::bind_method(D_METHOD("get_custom_font_size", "column"), &TreeItem::get_custom_font_size);
	ClassDB::bind_method(D_METHOD("set_custom_bg_color", "column", "color", "just_outline"), &TreeItem::set_custom_bg_color, DEFVAL(false));
	ClassDB::bind_method(D_METHOD("clear_custom_bg_color", "column"), &TreeItem::clear_custom_bg_color);
	ClassDB::bind_method(D_METHOD("get_custom_bg_color", "column"), &TreeItem::get_custom_bg_color);
	ClassDB::bind_method(D_METHOD("set_custom_as_button", "column", "enable"), &TreeItem::set_custom_as_button);
	ClassDB::bind_method(D_METHOD("is_custom_set_as_button", "column"), &TreeItem::is_custom_set_as_button);
	ClassDB::bind_method(D_METHOD("add_button", "column", "button", "id", "disabled", "tooltip_text"), &TreeItem::add_button, DEFVAL(-1), DEFVAL(false), DEFVAL(""));
	ClassDB::bind_method(D_METHOD("get_button_count", "column"), &TreeItem::get_button_count);
	ClassDB::bind_method(D_METHOD("get_button_tooltip_text", "column", "button_idx"), &TreeItem::get_button_tooltip_text);
	ClassDB::bind_method(D_METHOD("get_button_id", "column", "button_idx"), &TreeItem::get_button_id);
	ClassDB::bind_method(D_METHOD("get_button_by_id", "column", "id"), &TreeItem::get_button_by_id);
	ClassDB::bind_method(D_METHOD("get_button", "column", "button_idx"), &TreeItem::get_button);
	ClassDB::bind_method(D_METHOD("set_button", "column", "button_idx", "button"), &TreeItem::set_button);
	ClassDB::bind_method(D_METHOD("erase_button", "column", "button_idx"), &TreeItem::erase_button);
	ClassDB::bind_method(D_METHOD("set_button_disabled", "column", "button_idx", "disabled"), &TreeItem::set_button_disabled);
	ClassDB::bind_method(D_METHOD("set_button_color", "column", "button_idx", "color"), &TreeItem::set_button_color);
	ClassDB::bind_method(D_METHOD("is_button_disabled", "column", "button_idx"), &TreeItem::is_button_disabled);
	ClassDB::bind_method(D_METHOD("set_tooltip_text", "column", "tooltip"), &TreeItem::set_tooltip_text);
	ClassDB::bind_method(D_METHOD("get_tooltip_text", "column"), &TreeItem::get_tooltip_text);
	ClassDB::bind_method(D_METHOD("set_text_alignment", "column", "text_alignment"), &TreeItem::set_text_alignment);
	ClassDB::bind_method(D_METHOD("get_text_alignment", "column"), &TreeItem::get_text_alignment);
	ClassDB::bind_method(D_METHOD("set_expand_right", "column", "enable"), &TreeItem::set_expand_right);
	ClassDB::bind_method(D_METHOD("get_expand_right", "column"), &TreeItem::get_expand_right);
	ClassDB::bind_method(D_METHOD("set_disable_folding", "disable"), &TreeItem::set_disable_folding);
	ClassDB::bind_method(D_METHOD("is_folding_disabled"), &TreeItem::is_folding_disabled);
	ClassDB::bind_method(D_METHOD("create_child", "idx"), &TreeItem::create_child, DEFVAL(-1));
	ClassDB::bind_method(D_METHOD("get_tree"), &TreeItem::get_tree);