Inner workings

Windows

Mica Visual Studio works by using the DwmSetWindowAttribute function in the DWM API to apply backdrop, corner, and theme preferences. Because of this, you can think of it as a mini version of Mica For Everyone, only meant for Visual Studio. What differentiates it from Mica For Everyone though is its color changer. In Visual Studio, color themes modify the global merged dictionaries found in Application.Resources. Mica Visual Studio edits these resources, adding opacity to specific colors. This allows the backdrop to be seen by the user. Basically, if Mica For Everyone was a suit, Mica Visual Studio would also be a suit, but tailored way better (not that Mica For Everyone is bad; it's very well made and written. Mica Visual Studio is simply better for Visual Studio though, as it offers tighter integration because it's meant for VS, unlike Mica For Everyone, who is meant to be global). Additional backgrounds are removed from tool windows as needed (see Force transparency & Layered windows) to give a fully layered, transparent effect.

Popups

For acrylic menus, the process is different. For adding the acrylic effect, the semi-undocumented function SetWindowCompositionAttribute is used. It is used in place of the DwmSetWindowAttribute function as the ladder displays whether the window is focused while the former does not, allowing for the acrylic to always be shown. Then, the background of the menu is removed to unveil the acrylic. Finally, the menu's border and shadow are removed and replaced using DWM (via setting the menu's CornerPreference to Round).