The Problem: Custom Shortcuts Conflict (Windows + Shift + S)
When moving to Ubuntu 26.04, you likely want Windows + Shift + S to trigger a screenshot, but creating a "Custom Shortcut" for gnome-screenshot in the settings menu usually fails or does nothing.
Why? Modern Ubuntu uses an internal UI built directly into GNOME Shell. It gives priority to native keybindings and often ignores custom scripts or external commands that try to use the Super (Windows) key to prevent system-key hijacking.
The Solution: Reassigning Native Keybindings
Do not create a new "Custom Shortcut" at the bottom of the list. Instead, you must reassign the existing system function. This ensures the system recognizes the command correctly and launches the modern selection UI.
The Step-by-Step Guide
- Open Settings > Keyboard.
- Select View and Customize Shortcuts > Screenshots.
- Find the line: "Take a screenshot interactively".
- Click it and press your desired combination: Super + Shift + S.
- Click Replace or Reassign when the conflict warning appears.