Hi,

The extension was indeed quiet for a while, but development has resumed and v4.2.0 was just released today.

Priority bug: You are right, this was a real bug. The "Keep newer tab" option was not working correctly due to a comparison error with uninitialized timestamps. It is fixed in v4.2.0.

New Tab pages: These are already excluded from duplicate detection. Both about:newtab (Firefox) and chrome://newtab/ (Chrome) are treated as blank pages and ignored. They will not appear in the duplicate list.

Trailing slash: Also already handled. URLs are normalized before comparison and trailing slashes are always stripped, so https://example.com/ and https://example.com are treated as the same URL.

If you are still using the extension, updating to v4.2.0 should fix the priority issue.

By default, the extension only searches for duplicates within the currently focused window. To detect duplicates across all open windows, change the "Scope" setting to "All windows" in the Options page.

The strikethrough display you described is now available in v4.2.0: tabs that will be closed are shown with a strikethrough title, and the tab that will be kept is shown at full brightness. The "Close all" button has also been renamed to "Close duplicates" to make the intent clearer. The X next to each row closes that individual tab immediately. Hopefully that addresses the confusion.

For a badge or color on the browser tab itself: this is not possible with browser extension APIs. Extensions cannot style individual tabs in the tab bar. The extension icon badge already shows the duplicate count as a workaround.

For a quick close without opening the popup: you can assign a keyboard shortcut to "Close all duplicate tabs" in your browser's extension shortcut settings (chrome://extensions/shortcuts on Chrome, or about:addons on Firefox).

New Tab pages are already protected and cannot be auto-closed by the extension. Both about:newtab (Firefox) and chrome://newtab/ (Chrome) are excluded from duplicate detection before any comparison or whitelist logic runs. The "" entry would have no effect since the whitelist only applies to regular HTTP(S) URLs.

If you are seeing new tabs being closed, it is possible you have a custom new tab extension that replaces the default page with a regular URL. In that case, adding that URL to the whitelist would work. If this is still happening with the current version of the extension, please open an issue at https://github.com/Peuj/duplicate-tabs-closer/issues with more details.

On point 1: this is already available in v4.2.0. The hide-whitelisted button in the duplicate tabs footer makes the "Close duplicates" button skip whitelisted tabs, regardless of whether auto-close is on or off. New Tab and about:blank pages are also excluded from detection entirely, so they will never appear in the list or be affected by "Close duplicates".

On point 2 (notification on duplicate): the "Open popup on duplicate detected" option in the Options page already does this. When enabled, the popup opens automatically each time a new duplicate is detected, so you are immediately aware without any automatic closing.

On point 3 (choose new/old/nothing per duplicate): when the popup opens automatically (see point 2), you can see exactly which tabs are duplicates and use the X button next to any row to close whichever one you want. The global default for which tab is kept is also configurable via the Priority settings ("Keep older tab" / "Keep newer tab").

This is a known bug that was fixed in v4.2.0. Updating the extension should resolve it.

Thanks for the details.

So it happens with autoclose and newer. I'll search this way.

When you write "all duplicate tabs are closed" you means only the existing one and the new one?
Did you noticed if the older tab was completely loaded? or if both tabs were loading?

I guess you haven't be able to reproduce the problem with the same URL?

****Update ******
I've found something that can explain your problem.
I'll push a fix soon.

My next move is for the white/black list rules so it should match the one extra thing you need. :)

Thanks for the review!

Thanks for the report.
I've fixed the issue.

Thanks for the review.

Sadly the automatic prompt of popup is not supported by the new webextension API.

I'll also miss it.

Thanks for the feedback.

As you mention, there is probably a conflict with other tab add-ons.
Can you make a test with the suspected add-ons disabled to see if you reproduce the problem?
Can you give me the link to those add-ons? (for exemple I cannot find BarTab Plus)