### 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
popup_editor->hide();
	if (!popup_edited_item) {
		return;
	}
	if (popup_edited_item_col < 0 || popup_edited_item_col > columns.size()) {
		return;
	}
	TreeItem::Cell &c = popup_edited_item->cells.write[popup_edited_item_col];
	switch (c.mode) {
		case TreeItem::CELL_MODE_STRING: {
			c.text = p_text;
			
		} break;
		case TreeItem::CELL_MODE_RANGE: {
			c.val = p_text.to_float();
			if (c.step > 0) {
				c.val = Math::snapped(c.val, c.step);
			}
			if (c.val < c.min) {
				c.val = c.min;
			} else if (c.val > c.max) {
				c.val = c.max;
			}
			
		} break;
		default: {
			ERR_FAIL();
		}