Update: It appears this isn't new. This can be enabled in all development builds of Windows 8 and Windows 8.1. You can still try it out for yourself, continue reading for the original article.
The recent Windows 8.1 Update 1 leak (you can take a look at our hands-on video here) has revealed a number of new things which we can expect to see make its way to all Windows 8.1 PC's in April, including the ability to pin and run Modern UI apps from the taskbar. It also appears Microsoft may be working on a return of the highly popular Aero Glass theme.
From what can be enabled in the recent Windows 8.1 Update 1 leak, looks like a variation of the Glass theme can be enabled. In this build, it's extremely buggy and doesn't work as intended to. Dragging windows with Glass enabled lags and leaves many UI errors. So this is definitely a work in progress.
It's currently unclear if Microsoft have plans on bringing back the Glass theme to Windows. We've heard rumors countless times claiming that Aero would make a return one day, so this could be those first steps towards said features return. Until we have official concrete information, we'll just have to let this one sit and hope for the best.
So, I guess you're wondering how to do it? Well, it's pretty simple. Head over to Regedit.exe (WIN+R and type regedit) and go to the following directory: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows. From here, right click on 'Windows' and select New > Key and name it DWM. From there, create a Dword 32bit values and name it HideBlur, change the value to 1. Restart and voila! Remember it's pretty buggy!
Would you like to see Aero Glass return in the final build of Windows 8.1 Update 1?