What is the "Single Window" extension and how does it work?

This extension monitors newly opened tabs and determines whether they are opened in the correct window. Upon installation, it records the current window ID. Whenever a new tab is opened, the extension checks the tab's parent window and compares it to the stored window ID. If the tab opens in a different window, it is automatically moved back to the original window—similar to manually dragging a tab from one window to another.

The extension does not interfere with tabs opened by other extensions. It only acts on tabs using the http:// or https:// schemes, or tabs without a URL (such as about:blank). Tabs opened with chrome-extension:// or moz-extension:// URLs are ignored and will not be affected.

Note that this extension does not prevent websites from opening popup windows. Instead, if a popup is opened in a new window, it is briefly allowed and then moved to the original window. As a result, you may see the popup window appear for a short moment before it is relocated.

What's new in this version?

Please check the Logs section.

Although the extension works fine, I would like to allow a single popup window. How can I achieve this?

When the extension is installed, a button is added to the browser's toolbar area. Click the button once to temporarily disable single-window mode, allowing a popup window to open. Click the button again to re-enable single-window mode.

Alternatively, you can assign a keyboard shortcut to toggle single-window mode from the browser's extension manager, instead of clicking the toolbar button.

The enabled/disabled state is persistent and will be remembered across browser restarts.

Can I still open a new browser window when this extension is enabled?

Yes. You can open a new window using the browser's three-dot menu and selecting New Window. This type of window opening is not affected by the extension because it is explicitly initiated by the user.

You can also use the keyboard shortcuts Ctrl + N on Windows or Command + N on macOS to open a new window.

If multiple windows are open, the extension always uses the currently active window as the target for redirecting popup tabs.

What happens if I want to open a new private (incognito) window while this extension is enabled?

The extension does not intercept or interfere with private (incognito) window creation. Modern browsers keep normal and private browsing contexts completely separate, so they cannot be mixed or redirected by extensions.

I have some other extensions that do open new popup windows. Is this extension going to block those windows too?

No, this extension only intercepts HTTP://, HTTPS:// and about:blank window instances. If an extension opens an internal window, the URL starts with chrome-extension:// or moz-extension://. The extension ignores these types of window openings.

What does the "Check the type of the newly opened tab" option do?

This setting on the extension's options page controls whether the extension distinguishes between different types of new windows (such as regular browser windows or popup windows).

When enabled, the extension detects the window type and can behave differently depending on it. For example, you can use the related option—"If the newly opened tab is a 'popup' type"—to specify custom behavior for popups, such as skipping the extension's usual action and allowing the window to remain as a true popup.

By default, this option is disabled, meaning the extension ignores the window type and treats all newly opened windows as standard browser tabs (e.g., converting popups into regular tabs).