According to various reports and leaks, Windows 10 Sun Valley
upgrade is set to
bring back ’rounded corners’ from the days of Windows 7 and
Vista. As part of the redesign, top-level UIs will be
ditching sharp corners for rounded corners, representing a
change of aesthetic for Windows 10.

Back in the old days, Microsoft used both rounded and sharp
corners for top-level UIs in Windows, but the rounded corners
and aero effects were abandoned in favour of sharp corners and
Fluent Design.

Microsoft is now considering a new interface for the flyout
menus (DatePicker, TimePicker, etc) in Windows apps. The new
visual update for the flyout menu aims to deliver an “x-ray”
kind of effect where the colour is swapped in when the wheels
come to rest.

“This lets us do a colour swap dynamically even during the
scrolling, which gets a really smooth looking “x-ray” kind of
effect,” Microsoft noted in
a proposal posted on Github. As of January 21, the proposal
seems to have been approved.

In another Github
proposal, Microsoft highlighted the ’rounded corner’
changes coming to Windows 10 menus within the modern apps and
settings. Microsoft intends to update the padding/margins for
menus with additional spacing between items.

As you can see in the below screenshot, Microsoft is also
adding rounded corners on menu items and the menus will still
support Fluent Design.

Based on these mock-up screenshots, it is clear that the tech
giant is betting big on ’rounded corners’ to change the
interface of the OS and return to design style previously seen
during Windows 7 and Vista eras.

In addition to these app menus, Microsoft is also planning to
ditch sharp corners for Windows 10 app windows. For example,
Settings, Music, Photos, and other inbox apps could soon ditch
traditional sharp corners for rounded corners.

Windows 10’s new user interface improvements will begin showing
up in preview builds in the next few months, but the upgrade
won’t be released for the public until the second half of 2021.