Microsoft’s Windows 10 is popular enough on the desktop but doesn’t have much traction in its mobile/phone variety. One feature that promises to bridge the gap is the Continuum mode on some Windows 10 phones, which allows plugging in an external monitor (and optionally a keyboard/mouse) to get a PC-like interface. There are unfortunately a lot of rough edges in this mode which make it awkward to use.

Hardware required

Only some Windows 10 phones support Continuum; I’ve tested with a Lumia 950. Connecting to a monitor requires either an external dock widget (which provides HDMI/DisplayPort/USB-A ports and power over USB-C) or local-network streaming to a Windows 10 PC (a configuration I haven’t tested; I think it requires the Windows 10 Anniversary update).

If physical mouse and keyboard aren’t available, the phone’s touchscreen can be used as a trackpad and on-screen keyboard.

Theory

Because the Windows 10 “Universal Windows Platform” provides a common base between Windows variants for PC, mobile, game console, etc, an application written for UWP can be built & distributed once (as long as the differences in the UI are taken into account) and installed/run on all these various different form factors.

The “Continuum” mode in Windows 10 Mobile for phones allows the same device to run both the phone interface and the PC interface on different screens, with the locally installed apps able to run on either and pick their UI layout appropriately. Thus, you can use your phone like a tiny PC when ‘docked’ at home or at the office, then just unplug it on the go and use it as a phone: locally-stored data and installed apps are available in both modes.

Practice

There are three major problem areas: compatibility, performance, and UI.

Compatibility

First the big one: only Windows 10 Universal Windows Platform apps will work; just like the old “Windows RT” ARM edition of Windows 8, existing desktop apps are a no-go. This is an inherent limitation of the platform, and Microsoft’s bet is that developers will migrate to UWP for its various benefits. But that doesn’t help if you want to run something today that’s not available as a UWP app.

And of course, if the app isn’t pure .NET or HTML/JS, the developer will have to make sure they build it for ARM as well as x86/x64 – and it has to provide a phone interface to be installed, even if you only want to use it in Continuum mode.

Some phone apps don’t work in Continuum mode, including but not only legacy apps from Windows Phone 8. These can still be launched from the Start Menu or links from other apps, but will launch on the phone screen.

Performance

Phones are way beefier microcomputers than they used to be, but they’re still generally much slower and have less memory available than a PC. Complex web apps like Gmail or Facebook may run slower in Edge than you expect.

The Lumia 950 with the Microsoft display dock seems to be limited to 1920x1080 resolution, producing blurry or blocky output on a 4K Ultra-HD monitor compared to what a ‘real’ PC can do.

UI

The Continuum mode looks similar to the “tablet mode” on Windows 10 for PCs, but not exactly. Several major annoyances:

• Typeahead search doesn’t work as expected in the Start menu. I’m very used to hitting the Windows key then typing in ‘edge’ or ‘twitter’ or ‘powershell’ or whatever and hitting enter to launch – in Continuum, after launching the Start menu you must click into ‘All apps’ then click into the search box, and then you can start typing.
• No side-by-side apps on the external screen. On PCs and tablets you can click-n-drag an app to one side, then run another app on the other side. There is no way to do this in Continuum mode, which is especially wasteful given that external monitors tend to be 16:9 widescreen, which works great with side-by-side apps. (You can run a second app on the phone screen, as long as you’re not using the phone as a trackpad, but that’s not really what I want.)
• No mouse/trackpad speed control in Settings. The only mouse option available is left/right primary button; there’s no acceleration option so if your mouse cursor moves very slowly, you have to just deal with it.

Comparisons and competition

Some years before Windows 10, Canonical advertised a similar “use your phone as a PC” ability with a planned product “Ubuntu for Android”. This never really materialized, but the Ubuntu for Phones/Tablets that has come out (with a few products not widely used) does have some abilities to plug in a mouse/keyboard, and can even switch to a windowed mode unlike Windows 10’s Continuum which is full-screen only.

Conclusion

There’s some great ideas in there, and what works is technically impressive, but the edges are too rough for me to use on a regular basis… Even if the UI problems get cleared up, you have all the limitations of Windows 10 Mobile and few of the advantages of Windows 10 for PCs.