Second local test html File

Step 3: Select a word from this text, bring up the context menu by right clicking on this page. If the context menu does not have the expected "What's this?" menu item, then you have reproduced the bug. A more complicated reproduction using a public web page may be possible by continuing at step 4.

ADDITIONAL REPRO PROCEDURE

Step 4: Perform the remaining instructions using public web pages (that will change over time): start by following the link: Go to Web 101 Links   Clicking this link will automatically open a new tab.

Step 5: Verify that the "What's this?" context menu item appears on that page, it should be there (even though a new tab was created, see below for non-reproductions of this bug).

Step 6: In the article found on the newly-opened page, click on the second "HTMLGoodies" link, which should open a new tab. If it does not open a new tab then you clicked the wrong link or the page has changed.

Step 7: On the newly opened tab from step 6, make a selection and bring up the context menu by right clicking. If you do not see the expected "What's this?" menu item, then you have reproduced the bug.

NON REPRODUCING PROCEDURE (for my machine anyway)

NOTE: While all known reproductions of this bug require following a link that opens a new tab, and each such link has the attribute "target=_blank", as seen within the reproduction procedure this is by itself insufficient to guarantee reproduction of the bug. While on my machine reproducing the bug is 100% reliable by the foregoing procedures, on my machine I get 0% reproduction of this bug by doing the following.

Step 1: Follow the link: Go to a Mozilla https site having a link with the "target=_blank" attribute

Step 2: Verify that the "What's this?" context menu item appears on that page, it should appear if it works as it does on my machine. This in itself could be considered a non-repro of the bug. Nevertheless, continue.

Step 3: On the left column of that page, click on the "volunteer opportunities" link, which should open a new tab. If it does not open a new tab then you clicked the wrong link or the page has changed.

Step 4: On the newly opened tab from step 3, make a selection and bring up the context menu by right clicking. On my machine the "What's this?" menu item always appears which is another non-repro of the bug (it is as should be expected except for the bug).

DISCUSSION

Perhaps worth mentioning is a correlation (although a small sample) that I have noticed; so far, when the "What's this?" menu item does not appear as expected, the URI of the new tab where it fails has the same host address as the page from which it was launched. However, the lack of a DNS lookup, even as only a timing issue, appears unlikely to be relevant since such addresses are cached and the failures can be (again on my machine) repeated any number of times with the same outcome. In the mozilla non-repeat example, the first host is "donate.mozilla.org", which today resolved to 64.94.250.109, and the target host is "www.mozilla.org", which today resolved to 63.245.209.11. Again, this is a small sample correlation.<\p>

In these tests it is useful to be sure about the appearance of the add-on menu item by bringing up the menu a few times, because the add-on menu item can be temporarily absent for some time after a web page appears. This slowness occurs even if the menu item has appeared previously in a different browser window. It may be so slow to appear that a user can repeatedly, although only temporarily, open the context menu without the expected add-on menu item appearing. However, slowness of the browser to get add-on context menu items correct before a user can bring it up is likely a separate issue because this failure is not temporary.<\p>