Highlighting text causes Firefox to freeze

[ssc-css]

Description of the bug

When i select the text on my page it happens that the Firefox-Tab freeze.
I think it has to do with the tooltips.

Expected behavior

The Firefox should not freeze.

Minimal reproducible example

@Route("test")
@PageTitle("Test")
@Menu(order = 1, icon = "vaadin:clipboard-check", title = "Test")
public class TestView extends Main {

	public TestView() {
		FlexLayout layout = new FlexLayout();
		layout.setFlexDirection(FlexLayout.FlexDirection.COLUMN);

		Button t1 = new Button("test 1");
		t1.setTooltipText("test 1");
		TextField field1 = new TextField("Field 1");
		field1.getTooltip();
		TextField field2 = new TextField("Field 2");
		field2.getTooltip();
		Button t2 = new Button("test 2");
		t2.setTooltipText("test 2");

		layout.add(new H2("Headline"), field1, t1, field2, t2, new H3("EndLine"));
		add(layout);
	}

}

Versions

• Vaadin / Flow version: 24.9.3
• Java version: 21
• OS version: Windows 7
• Browser version (if applicable): Firefox Browser 144.0 (64-Bit)
• Application Server (if applicable):
• IDE (if applicable):

[TatuLund]

I am able to reproduce this on Firefox /w Windows 11. There is no errors in browser console, so pretty hard to give quick analysis what goes wrong.

[yuriy-fix]

Might provide additional insights: vaadin/flow-components#2296

[DiegoCardoso]

It does not seem to be related to the Tooltip per se, but it does happen when there's an element inside the tooltip slot of the TextField. This is enough to make it freeze:

		Button t1 = new Button("test 1");
		TextField field = new TextField("Field 2");
    var dummy = new Div();
    dummy.setText("Dummy");
    dummy.getElement().setAttribute("slot", "tooltip");
    field.getElement().appendChild(dummy.getElement());
		Button t2 = new Button("test 2");

		layout.add(new H2("Headline"), t1, field, t2, new H3("EndLine"));

It happens when the selection passes by both Button instances.

[TatuLund]

Is it a bug in Firefox?

[DiegoCardoso]

It might be. The performance profile seems to point to some underlying issue in the engine. But I am yet to isolate this bug further to confirm it.