Why does isDisplayed return true for option element with display none?

[Lee Read]

First, my apologies, I am guessing this has been answered before. I did try many searches but I failed to find an answer.

I've noticed that isDisplayed returns true for an option element that has a CSS styling of display: none;.

I'm not at all suggesting this is wrong, I just don't understand the rationale for this behavior yet and am hoping to learn.

I do see a comment in the Selenium source code on isShown that says option elements have special treatment:

* Options and Optgroup elements are treated as special cases: they are 

* considered shown iff they have a enclosing select element that is shown.

but I don't see an explanation as to why.

Selenium's selectPage.html test file has an example to illustrate:

<select id="visibility">
  <option value="regular" class="regular">Regular</option>
  <option value="disabled" disabled="disabled" class="disabled">Disabled</option>
  <option value="hidden" style="visibility: hidden;" class="hidden">Hidden</option>
  <option value="invisible" style="display: none;" class="invisible">Invisible</option> 

</select>

If hit the above with the following Java code (using Selenium 4.3.0, chromedriver 103.0.5060.53 and Chrome 103.0.5060.114 on macOS 10.15.7 with OpenJDK Temurin-11.0.15+10):

package com.dlread.seleniumplay;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class Play {

  public static void main (String args[]) {
    WebDriver driver = new ChromeDriver();

    driver.get("file:///Users/lee/proj/oss/SeleniumHQ/selenium/common/src/web/selectPage.html");

    System.out.println ("regular displayed: " + driver.findElement(By.cssSelector("[class='regular']")).isDisplayed());
    System.out.println ("hidden displayed: " + driver.findElement(By.cssSelector("[class='hidden']")).isDisplayed());
    System.out.println ("invisible displayed: " + driver.findElement(By.cssSelector("[class='invisible']")).isDisplayed());
    driver.close();
  }
}

I see the following output:

regular displayed: true
hidden displayed: true
invisible displayed: true

Here's what I see if I manually open selectPage.html in Chrome:

The Regular and the Hidden items are shown, so a return of true from isDisplayed makes sense to me.

I was (probably naively) expecting isDiplayed to return false for the Invisible item.

I'm sure this is probably Selenium 101, but would somebody be so kind to educate me here?

[Lee Read]

Forgot to mention: If there is any interest, I'd be happy to submit a PR with updates to Selenium docs in this area,  once I understand the rationale for the current behavior.

[Lee Read]

I'm digging a bit into the commit history.

If I understand correctly (which I might not) this behavior was introduced way back in August of 2010.

The commit message is brief:

SimonStewart: Updating the atoms.
   
r9490

I am guessing r9490 is likely an issue reference. A little more digging tells me Selenium used to be hosted on (the now retired) Google Code, and that its issues are archived here.

Alas, I don't see an issue that maps to 9490 in the archive (it could be that I don't understand the mapping).