[Linux/Flatpak] Extension permission dialog cut off - Cannot install any extensions

[bastndev]

Environment

• OS: Debian 12
• Edge Version: 141.0.3537.71-1 (Flatpak)
• Installation Method: Flatpak (com.microsoft.Edge)
• Build Age: 7 days ago
• Note: Flatpak wrapper is not verified by, affiliated with, or supported by Microsoft

Bug Description

The extension installation permission dialog is rendered partially outside the viewport,
making it impossible to install ANY extension. The dialog appears at the top-right
corner but is cut off at the bottom, hiding the action buttons completely.

Steps to Reproduce

1. Open Microsoft Edge 141.0.3537.71-1 on Debian 12 (Flatpak installation)
2. Navigate to Edge Add-ons store (microsoftedge.microsoft.com/addons)
3. Try to install ANY extension (tested with "Material Icons for GitHub" and others)
4. Click "Add to Microsoft Edge"
5. Permission dialog appears but is truncated at the top-right corner

Expected Behavior

• Dialog should display fully within browser viewport
• "Add extension" and "Cancel" buttons should be visible and clickable
• User should be able to review permissions and complete extension installation

Actual Behavior

• Dialog appears anchored at top-right corner
• Bottom portion (approximately 50%) is cut off/rendered outside viewport bounds
• Action buttons (Add/Cancel) are NOT visible at all
• Cannot click anywhere to approve or cancel installation
• No keyboard shortcut works (Tab/Enter/Esc have no effect)
• Dialog remains stuck in this state until page is reloaded

Impact

CRITICAL SEVERITY: This bug makes it completely impossible to install ANY browser
extension through the UI. This is a blocking issue that prevents basic browser functionality.

• ❌ Cannot install any extensions
• ❌ Cannot approve permission requests
• ❌ No workaround available
• ✅ Happens with 100% of extensions tested
• ✅ Persists across browser restarts and system reboots

Screenshots

The red arrow shows where the dialog is cut off. The action buttons are completely invisible.

Reproducibility

• Frequency: 100% (every single extension installation attempt fails)
• Tested with: Multiple different extensions including:
  • Material Icons for GitHub
  • Other extensions (all fail identically)
• Persistence: Issue persists across:
  • Browser restarts
  • System reboots
  • Different extensions
• Scope: Affects ALL extensions without exception

System Details

Edge Version: 141.0.3537.71-1
Platform: Linux (Flatpak)
Installation: Flatpak package (not official Microsoft build)
Package Size: 3.5 GB (includes 1.6 GB data + 1.9 GB cache)
Desktop Environment: Likely GNOME/KDE (Flatpak on Debian 12)
Windowing System: Uses legacy windowing system (marked as "Unsafe")

Additional Technical Context

• This is clearly a Flatpak-specific issue on Linux
• The Flatpak wrapper warning is visible: "This wrapper is not verified by, affiliated with, or supported by Microsoft"
• Software is marked as "Proprietary" and "Unsafe" (legacy windowing)
• Likely root causes:
  1. Incorrect viewport boundary calculations for Flatpak sandbox
  2. Window decoration height not accounted for in dialog positioning
  3. Coordinate system mismatch between Flatpak sandbox and native window manager
  4. Dialog positioning logic assumes Windows/macOS behavior

Priority Justification

This should be treated as HIGH/CRITICAL PRIORITY because:

1. ✅ Completely blocks core functionality: Users cannot install extensions at all
2. ✅ 100% reproduction rate: Affects every single extension installation attempt
3. ✅ No workaround exists: Users are completely stuck
4. ✅ Growing user base affected: Flatpak is a major Linux distribution method
5. ✅ Recent regression: Version 141.0.3537.71-1 is only 7 days old

Suggested Fix

The dialog positioning logic needs to account for:

• Flatpak sandbox viewport boundaries
• Linux window manager decoration heights
• Different coordinate systems on Linux vs Windows/macOS
• Safe margin from viewport edges

Related Issues

• May be related to historical issue Feedback on TitleBarCustomization #165 (closed in 2020)
• This appears to be either a regression or new manifestation of Linux dialog positioning problems

Workaround Status

❌ No workaround available

• Keyboard navigation doesn't work
• Zoom adjustments don't help
• Full-screen mode doesn't fix it
• Cannot use extensions at all on this platform

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This is a blocking bug that makes Microsoft Edge on Linux/Flatpak unable to install
extensions, which is a fundamental browser feature.