### Godot version

master ([06ccbfe](https://github.com/godotengine/godot/commit/06ccbfe8eec6e840db3df2360dc2804386f940b8))

### System information

PopOS 22.04

### Issue description

Sometimes the doc page is broken when the engine is closed and then restarted.
Closing the doc and opening it again fixes it.

![2023-05-27_22-15](https://github.com/godotengine/godot/assets/3624853/ed202a55-03e8-420a-bc1c-ccfc7f7cd02a)


### Steps to reproduce

- Open a documentation page for any node
- Restart Godot

### Minimal reproduction project

NA

EDIT : Added the commit hash @Calinou 
ERR_FAIL_COND(p_event.is_null());
	Ref<InputEventMouseButton> b = p_event;
	if (b.is_valid()) {
		if (b->get_button_index() == MouseButton::LEFT) {
			if (b->is_pressed() && !b->is_double_click()) {
				scroll_updated = false;
				ItemFrame *c_frame = nullptr;
				int c_line = 0;
				Item *c_item = nullptr;
				int c_index = 0;
				bool outside;
				selection.drag_attempt = false;
				_find_click(main, b->get_position(), &c_frame, &c_line, &c_item, &c_index, &outside, false);
				if (c_item != nullptr) {
					if (selection.enabled) {
						selection.click_frame = c_frame;
						selection.click_item = c_item;
						selection.click_line = c_line;
						selection.click_char = c_index;
						
						if (selection.active) {
							if (_is_click_inside_selection()) {
								selection.drag_attempt = true;
								selection.click_item = nullptr;
							} else {
								selection.from_frame = nullptr;
								selection.from_line = 0;