pomodorolm displays a black screen when launched via Flatpak on Hybrid Graphics Systems (X11)

[EnginKarahan]

🪲 Describe the bug
pomodorolm launches successfully in the background—the timer logic is running, as confirmed by hearing the ticking sound when clicking inside the window—but the main application window displays only a solid black screen.

📑 To Reproduce
Steps to reproduce the behavior:

1. Install pomodorolm via Flatpak from Flathub.
2. Launch the application (e.g., from the Linux Mint Application Menu).
3. Observe the resulting application window.
4. See error (Black screen, audible ticking upon click).

☑️ Expected behavior
The application window should load correctly, displaying the functional GUI as shown in the provided screenshots (showing the timer, settings, etc.).

🖼️ Screenshots

🧑‍💻 Desktop (please complete the following information):
OS: Linux Mint
Version: 22.2 Zara (based on Ubuntu 24.04 Noble)
Desktop Environment: Cinnamon v: 6.4.8
Display Server: X.Org v: 21.1.11 (X11)
⚙️ Additional context
This issue could be related to Hybrid Graphics (Intel UHD 630 integrated + NVIDIA GeForce MX150 dedicated). Since the application is a Flatpak, it might be defaulting to the integrated Intel GPU, causing the GTK/OpenGL rendering to fail while the underlying application logic continues to run.

🍅 Pomodorolm information
How did you install pomodorolm?
Flatpak (Flathub)

What version number are you using?
Version: 0.6.1 (Name: org.jousse.vincent.Pomodorolm)

[vjousse]

Well… I have to admit that I don’t know how to reproduce this error as I don’t have the same setup locally.
Did you try the fixes related to nvidia that are explained here https://github.com/vjousse/pomodorolm?tab=readme-ov-file#linux ?