### 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();
	TreeItem::Cell &selected_cell = p_selected->cells.write[p_col];
	bool switched = false;
	if (r_in_range && !*r_in_range && (p_current == p_selected || p_current == p_prev)) {
		*r_in_range = true;
		switched = true;
	}
	bool emitted_row = false;
	for (int i = 0; i < columns.size(); i++) {
		TreeItem::Cell &c = p_current->cells.write[i];
		if (!c.selectable) {
			continue;
		}
		if (select_mode == SELECT_ROW) {
			if (p_selected == p_current && (!c.selected || allow_reselect)) {
				c.selected = true;
				selected_item = p_selected;
				selected_col = 0;
				if (!emitted_row) {
					emit_signal(SNAME("item_selected"));
					emitted_row = true;
				}
			} else if (c.selected) {
				if (p_selected != p_current) {