### 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
if (p_pos.y - theme_cache.offset.y > (p_draw_size.height)) {
		return -1; 
	}
	if (!p_item->is_visible()) {
		return 0;
	}
	RID ci = get_canvas_item();
	int htotal = 0;
	int label_h = compute_item_height(p_item);
	bool rtl = cache.rtl;
	
	label_h += theme_cache.v_separation;
	
	bool skip = (p_item == root && hide_root);
	if (!skip && (p_pos.y + label_h - theme_cache.offset.y) > 0) {
		
		ERR_FAIL_COND_V(theme_cache.font.is_null(), -1);
		int ofs = p_pos.x + ((p_item->disable_folding || hide_folding) ? theme_cache.h_separation : theme_cache.item_margin);
		int skip2 = 0;
		for (int i = 0; i < columns.size(); i++) {
			if (skip2) {
				skip2--;
				continue;
			}
			int w = get_column_width(i);
			if (i == 0) {
				w -= ofs;
				if (w <= 0) {