The Window Depth Effect
Windows 10 relies on subtle visual cues to help users distinguish between multiple overlapping applications. One of the primary cues is controlled by the “Show shadows under windows” setting. When this is enabled, the active window (the one currently in focus) casts a large, soft drop shadow onto the windows and desktop behind it. Background windows cast slightly smaller shadows. This creates a pseudo-3D effect, visually separating the active application from the background clutter.
While this drop shadow looks elegant, it is purely cosmetic and requires the Desktop Window Manager (DWM) to constantly calculate and render alpha-transparent blur effects as you drag windows around the screen. On older laptops, budget tablets, or within Virtual Machines, rendering these dynamic shadows can cause noticeable input lag and screen tearing when moving applications. Furthermore, some users simply prefer the flat, sharp-edged aesthetic of older operating systems. Disabling this effect removes the blur and forces windows to stack perfectly flat against one another.
How to Turn Off Window Shadows
You can remove the drop shadows from all application windows via the advanced system performance settings.
- Click the Start button and type Advanced system settings.
- Select View advanced system settings from the search results. This directly opens the System Properties window to the Advanced tab.
- Under the Performance section near the top, click the Settings… button.
- A new “Performance Options” window will appear. Ensure you are on the Visual Effects tab.
- Scroll through the list of effects and locate the checkbox labelled Show shadows under windows.
- Click the checkbox to remove the checkmark.
- Click Apply, and then click OK.
Your application windows will instantly lose their dark borders. When they overlap, they will now sit perfectly flat with hard, distinct edges, saving a small amount of graphics processing power.