Depending on how I launched it, Flameshot either failed to capture screenshots properly or behaved inconsistently. Multi-monitor support was another issue, with only one of my three screens being captured.

After trying several approaches, the solution turned out to be surprisingly simple: run Flameshot through XWayland instead of its native Wayland backend.

1. Install Flameshot

sudo apt install flameshot

2. Force Flameshot to use XWayland

The key is the QT_QPA_PLATFORM environment variable.

Instead of launching Flameshot normally:

flameshot gui

Launch it with:

QT_QPA_PLATFORM=xcb flameshot gui

The xcb value tells Qt to use its X11 backend, which runs through XWayland when the desktop session uses Wayland.

This fixed the screenshot capture issues on my setup, including interactive region selection across all three monitors.

Importantly, the desktop itself remains on Wayland. Only Flameshot uses the X11 compatibility layer.

3. Save screenshots to disk and copy them to the clipboard

I wanted the following workflow:

  1. Press the Print Screen key.
  2. Interactively select a region on any monitor.
  3. Annotate the screenshot.
  4. Automatically save it to disk and copy it to the clipboard.

First, create a directory for screenshots:

mkdir -p ~/Pictures/Screenshots

Then launch Flameshot with:

QT_QPA_PLATFORM=xcb flameshot gui \
  --path ~/Pictures/Screenshots \
  --clipboard

The command combines three useful features:

  • gui enables interactive selection and annotation.
  • --path specifies where screenshots are saved.
  • --clipboard copies the captured image to the clipboard.

Both saving and clipboard copying work correctly on my setup.

4. Bind Flameshot to the Print Screen key

To make the process seamless, configure a custom keyboard shortcut in GNOME.

Open:

Settings → Keyboard → Keyboard Shortcuts → Custom Shortcuts

Create a shortcut with the following settings:

Name: Flameshot

Command:

bash -c 'QT_QPA_PLATFORM=xcb flameshot gui --path ~/Pictures/Screenshots --clipboard'

Shortcut: Print

If GNOME already uses the Print key for its built-in screenshot tool, remove that existing binding first.

The bash -c wrapper also worked reliably when launching Flameshot from a keyboard shortcut, whereas my earlier shortcut configuration did not.

5. That's it

No need to switch the entire desktop to X11, replace GNOME, or install additional screenshot utilities.

The complete solution is one command:

bash -c 'QT_QPA_PLATFORM=xcb flameshot gui --path ~/Pictures/Screenshots --clipboard'

With this shortcut, Flameshot now works as expected:

  • Interactive screenshot selection
  • Support for all three monitors
  • Built-in annotation tools
  • Automatic saving to disk
  • Copying screenshots to the clipboard
  • Launching directly from the Print Screen key

On my Ubuntu 26.04 setup, forcing Flameshot to use Qt's X11 backend through XWayland resolved the capture and multi-monitor issues without requiring me to switch the entire desktop session to X11.