Fenestrae is software for Windows 11 that solves two common problems in multi-monitor setups: windows scattering whenever the display configuration changes, and the tedious manual alignment of windows. The application captures the complete desktop state (position, size, and application of each window) into named profiles, bound to the specific monitor topology using a system fingerprint. Additionally, it includes an arrange mode activated by Ctrl+Win+A that displays a full-screen transparent overlay, enabling window snapping to each other, to monitor edges, center lines, and a configurable grid, with visual distance indicators and alignment guides.