### 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
ERR_FAIL_INDEX_V(p_column, columns.size(), -1);
	
	int min_width = columns[p_column].custom_min_width;
	
	if (show_column_titles) {
		min_width = MAX(theme_cache.font->get_string_size(columns[p_column].title, HORIZONTAL_ALIGNMENT_LEFT, -1, theme_cache.font_size).width + theme_cache.panel_style->get_margin(SIDE_LEFT) + theme_cache.panel_style->get_margin(SIDE_RIGHT), min_width);
	}
	if (!columns[p_column].clip_content) {