### 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 (pressing_for_editor && popup_pressing_edited_item && (popup_pressing_edited_item->get_cell_mode(popup_pressing_edited_item_column) == TreeItem::CELL_MODE_RANGE)) {
			
			popup_edited_item = popup_pressing_edited_item;
			popup_edited_item_col = popup_pressing_edited_item_column;
			popup_pressing_edited_item = nullptr;
			popup_pressing_edited_item_column = -1;
			if (!range_drag_enabled) {
				
				Vector2 cpos = mm->get_position();
				if (rtl) {
					cpos.x = get_size().width - cpos.x;
				}
				if (cpos.distance_to(pressing_pos) > 2) {
					range_drag_enabled = true;
					range_drag_capture_pos = cpos;
					range_drag_base = popup_edited_item->get_range(popup_edited_item_col);
					Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_CAPTURED);
				}
			} else {
				const TreeItem::Cell &c = popup_edited_item->cells[popup_edited_item_col];
				float diff_y = -mm->get_relative().y;
				diff_y = Math::pow(ABS(diff_y), 1.8f) * SIGN(diff_y);
				diff_y *= 0.1;
				range_drag_base = CLAMP(range_drag_base + c.step * diff_y, c.min, c.max);
				popup_edited_item->set_range(popup_edited_item_col, range_drag_base);
				item_edited(popup_edited_item_col, popup_edited_item);
			}
		}
		if (drag_touching && !drag_touching_deaccel) {
			drag_accum -= mm->get_relative().y;