The Edge sidebar: a second place for the apps you check often

Most searches for the Edge sidebar come from one of two situations. Either the pane has appeared on the right edge of the browser and the question is how to control it, or the pane is known to exist and the question is whether it can hold the handful of tools that get checked twenty times a day. Those are different questions with different answers, and the second one is where the sidebar's design turns out to be more interesting than the usual walkthroughs suggest. The feature is not a bookmark strip. It is a second content area inside the browser window, with its own rules about what stays open and when.

What the pane actually is

Microsoft's own documentation for extension developers gives the clearest definition, because it has to be precise for people writing code against it.

The sidebar is a persistent pane that's located on the side of Microsoft Edge. The sidebar pane coexists with the primary content of the browser. The sidebar reduces the need to constantly switch between tabs, resulting in a more productive browsing experience. Source: learn.microsoft.com

Three words in that definition carry the design. Persistent means the pane survives navigation, so the content in it does not reload every time the main area changes. Coexists means it is not a modal overlay competing for the same rectangle. And side means the browser window is now divided into two regions with different lifetimes, one that changes constantly and one that is meant to stay put.

The underlying machinery is the Side Panel API, exposed to extensions as chrome.sidePanel. Microsoft notes that the Chrome interface calls the same concept a side panel. An extension declares a sidePanel permission and a side_panel entry in its manifest pointing at an HTML file, and that page then runs in the same trusted extension context as any other extension page, with access to the whole extension API surface. This matters for a practical reason: the sidebar is not limited to what Microsoft chose to put there. Anything distributed as an extension can claim that space.

What ships in it

The built-in apps are documented because administrators need to be able to name them in policy. Microsoft lists Copilot, Shopping, Tools, Games, Microsoft Office, Outlook, Eco tree, Image Creator, OneNote, and Designer among the built-in sidebar apps.

There is a page inside the browser that settles arguments about what is actually installed. Navigating to edge://sidebar-internals produces a JSON manifest covering every sidebar app, including an extension_id for each one and, for most of them, a target object containing the URL the app loads. Microsoft points administrators at that page precisely because the list changes between versions and the names in the interface do not always match the identifiers underneath.

One app behaves differently from all the others. The Search app has no URL at all, which means URL based policy cannot touch it. Blocking it requires naming its extension ID, and Microsoft publishes that ID rather than making administrators go and look it up.

That list is documented in the present tense in the administration guidance, and the next section explains why the present tense is temporary.

The app list is being retired

Anyone planning around the sidebar needs one more fact, and it changes the shape of the decision. The column of app icons is going away.

Microsoft's release notes for Stable version 150.0.4078.48, published on July 2, 2026, announced that the sidebar app list would be retired in the near future. The note is specific about the stages: new apps can no longer be added to the sidebar, apps currently pinned in the app tower will be removed in a future update, and sidebar app policies will no longer be supported, with any configured policies no longer applied.

Four weeks later the note came back in the past tense for one audience. The release notes for Stable version 151.0.4129.59, published on July 31, 2026, state that the sidebar app list is retired for enterprise users, with the same three consequences written as completed facts rather than predictions. The reason given in both notes is one sentence long and identical: Microsoft is simplifying Edge. The same version carried a comparable notice about the file transfer feature being retired in the near future, which suggests the sidebar is not being singled out.

Pace matters here too. Microsoft announced in Stable version 152.0.4191.53, published on August 27, 2026, that Edge had completed its move to a two week cadence for major versions, and Stable reached 154.0.4258.37 on September 24, 2026. A feature that has been publicly marked for retirement does not survive many cycles at that speed.

What survives the retirement is worth being precise about, because the announcements refer to the app list rather than to the pane. Open in sidebar is governed by its own policy and is not named in the retirement notes. Copilot is managed separately from the app tower. Extensions that draw their own interface through the Side Panel API use the Chromium level mechanism rather than Microsoft's app catalogue. So the outcome is a sidebar that still exists as a place to put one thing, without a shipped list of things to put in it.

The practical consequence for anyone who had pinned six services to the app tower is that the icons are the part that disappears, not the accounts or the data behind them. Pinned apps were URLs and nothing more. Still, writing down what was pinned before the icons vanish is considerably easier than reconstructing the list from memory afterwards, and it is the one preparation step worth taking now.

Putting a site of your own in it

The sidebar is not restricted to the shipped apps, and this is the part relevant to anyone who keeps a chat tool or a ticket queue permanently in view. Any site can be opened in the pane through Open in sidebar, found under Settings and more. The behaviour is governed by a policy called EdgeOpenInSidebarEnabled, and Microsoft documents that policy as enabled by default, which means it is present unless an employer has deliberately switched it off.

Adding and removing apps is separate. Hovering over the plus sign in the sidebar reveals a Customize control, and that path is governed by EdgeSidebarCustomizeEnabled, also enabled by default. An app added this way can be removed again, and the order of the icons can be rearranged by dragging them.

That combination, an arbitrary URL plus a persistent pane, is the closest a mainstream browser comes to treating a web service as an application rather than as a page. It is worth being clear about the limit, though. There is one pane. Two tools that both need to be visible at the same time cannot both have it, and that constraint is not a bug to be worked around. It follows from the pane being a single region of the window.

The known gap worth planning around

Microsoft documents a defect in the persistence behaviour, and it is the kind that erodes trust in the feature over a week of use rather than in the first five minutes.

The sidebar stays open while navigating between tabs. But when a user switches to a tab in which the sidebar was previously open, the sidebar is not automatically displayed again. Microsoft records this as a known issue with a tracked issue number rather than as intended behaviour.

The consequence is that the pane's persistence is partial. It follows the window, not the tab, and switching tabs in certain orders leaves the pane closed with no indication that it was ever open. For a tool checked on a rhythm, a chat client or a queue, this is the difference between a place something lives and a place something sometimes is. Anyone evaluating the sidebar as a home for always visible tools should test that specific sequence first, because it determines whether the pane needs reopening by hand several times a day.

What an administrator can do to it

On a managed Mac or PC the sidebar may not be yours to configure, and it is worth knowing the shape of the controls before concluding that a setting is missing.

Policy	What it controls
HubsSidebarEnabled	Allows or blocks the sidebar entirely. Blocking it also blocks every sidebar app
EdgeOpenInSidebarEnabled	Whether Open in sidebar is offered. Enabled by default
EdgeSidebarCustomizeEnabled	Whether users can add or delete sidebar apps. Enabled by default
EdgeSidebarAppUrlHostBlockList	Blocks specific sidebar apps by URL, from Edge 127 onward. Setting it to an asterisk blocks all of them except Search
EdgeSidebarAppUrlHostAllowlist	Exempts named apps from that block list, from Edge 131 onward
ExtensionInstallBlockList	The only route to blocking the Search app, which has no URL

Two details in Microsoft's documentation explain symptoms that otherwise look like bugs. Blocking the sidebar also removes access to the Discover app in the toolbar, from Edge 111 onward, so a missing toolbar button can be a side effect of a sidebar policy. And from Edge 116 onward the sidebar policy applies inside Progressive Web Apps as well, meaning an installed web app can inherit a restriction set for the browser.

Microsoft also reuses extension policies to manage sidebar apps, and states that the reuse is intentional and meant to promote flexibility. That is why the sidebar apps turn up in extension block lists at all, and why identifiers from edge://sidebar-internals are needed to write those lists.

Where the sidebar runs out

The sidebar solves one instance of a general problem: a tool that needs to be visible while other work happens. It solves exactly one instance, because there is one pane, and it solves it inside one browser.

The general version of the problem looks different, and the retirement of the app list makes it sharper rather than easier, because the shipped answer to keeping several sites at hand is the part that went away. Six services that each need their own session, their own notification behaviour, and their own window, several of them with two accounts apiece. A single pane cannot hold that, and neither can a row of tabs, since a tab is a place the window sometimes is rather than a place a tool lives. The category of tool built for that shape is the app aggregation browser, which gives each service a persistent window of its own instead of a shared strip of screen. What that looks like in practice is described under Features, the grouping of several services per task is covered in Workspaces, and the list of services known to work that way is at Supported apps.

There is one more difference worth naming, because it is the one people notice on the second day rather than the first. A pane inside a browser window is not an application as far as the operating system is concerned. It cannot be reached from the app switcher, it cannot be assigned to a display, and closing the window that holds it closes it too. A window can do all three. That is a small distinction on paper and a large one in the hands, because it decides whether a tool is somewhere you go or somewhere you happen to be.

What to change first

Open one tool in the sidebar with Open in sidebar, use it for a week, and pay attention to how often the pane needs reopening after tab switches. If one tool is enough, the sidebar is the whole answer and nothing else needs installing. If the honest count is four or more, the thing to change is the window model rather than the pane, and SpaceDeck is built around that.