Firefox desktop now presents three window types for different jobs: Classic, Private, and the beta Smart Window. Mozilla’s point is not that one replaces the others. Each changes what the browser retains, what can be customized, and whether an AI assistant can work with context you choose to share.
What each window does
Classic Window is the normal, most configurable Firefox experience. It supports the full extension library, toolbar and control customization, advanced settings, and Firefox Sync for history, bookmarks, and tabs. It is the sensible default for routine browsing and for people who have built a personalized browser setup.
Private Window limits local session traces after its final private window closes. Firefox does not retain visited pages in History or address-bar suggestions, form entries are not saved for autocomplete, and private cookies live only in memory. Extensions are disabled there by default unless explicitly allowed. Private browsing is useful on a shared machine or when a session should not remain in local history; it does not make a user anonymous to websites, employers, or network providers.
Smart Window is an optional AI-assisted experience rolling out in beta to users in the US, Canada, and France. Its assistant can summarize pages, compare information, make recommendations, plan tasks from open tabs, and retrieve current web information with visible sources. Mozilla says users can select one of three models or bring their own model.
Why the distinction matters
Window choice is now a privacy and workflow decision, not just a cosmetic preference. Smart Window can use the page, open tabs, and recent browsing only when the user chooses to share that context. Its optional memories can learn from Smart Window chats, browsing activity in Smart and Classic windows, or both. Mozilla says those memories are stored locally and can be deleted, but users should still decide deliberately what browsing context is appropriate for an AI-assisted task.
Practical selection checklist
- Use Classic for everyday work, extensions, sync, and deep customization.
- Use Private for a one-off session on a shared device or when local history and cookies should not persist.
- Use Smart for research, trip planning, comparison shopping, or multi-tab work where an assistant can save time.
- Before sharing tabs with Smart Window, close unrelated work, financial, HR, customer, or administrative pages.
- Review the selected AI model, memory choice, region availability, and displayed sources before relying on an answer.
Notes for IT teams
Smart Window remains beta and regional, so enterprise teams should not assume universal availability or deploy it as a standard workflow without testing. Assess browser policies, extension behavior, identity flows, data classification, and whether staff understand the difference between local private browsing and network anonymity. A short internal guide can prevent users from placing sensitive tabs into an AI context accidentally.
Conclusion
Classic remains the customizable home base; Private is for keeping a session out of local browser records; Smart is a controlled, AI-assisted workspace for tasks that benefit from context. The useful habit is to choose the window before starting the task, then share only the information that task requires.
Source
Mozilla Blog: Classic, Private, or Smart? Choose the Right Firefox Window.