Double-click byte selection not working in HexEditorV2

[abbaye]

Double-click byte selection not working in HexEditorV2

🐛 Bug Description

Double-clicking on a byte in HexEditorV2 should select all bytes with the same value, but the selection is not being applied correctly.

Expected Behavior

When double-clicking on a byte (e.g., value 0x41):

1. All bytes in the visible region with the same value should be selected
2. SelectionStart should be set to the first match position
3. SelectionStop should be set to the last match position
4. The selected bytes should be visually highlighted

Actual Behavior

• Double-click is detected (confirmed by debug logs)
• SelectAllBytesWith() method is called
• But the selection is not visually applied or doesn't work as expected

Technical Details

Implementation:

• Feature implemented in commit bbec374 - "Fix double-click select to use real selection"
• Auto-highlight feature works correctly (commit dbd0522)
• Uses real selection (SelectionStart/SelectionStop) instead of visual highlighting

Key Files:

• V2/HexEditorV2.xaml.cs - HexViewport_ByteDoubleClicked() handler
• V2/HexEditorV2.xaml.cs - SelectAllBytesWith() method
• V2/ViewModels/HexEditorViewModel.cs - Selection management

Debug Logging:
Debug logs have been added to:

• HexViewport_ByteDoubleClicked() - Shows when double-click is detected
• SelectAllBytesWith() - Shows search results and selection being set
• Output visible in StatusText and System.Diagnostics.Debug.WriteLine()

Steps to Reproduce

1. Open a file in HexEditorV2
2. Double-click on any byte in the hex view
3. Observe that the selection doesn't work as expected

Environment

• HexEditorV2 (V2 architecture with MVVM)
• Insert mode implementation active
• Custom DrawingContext rendering

Related Features

• ✅ Auto-highlight feature works (highlights matching bytes in yellow)
• ❌ Double-click selection broken

Priority

Medium - V1 compatibility feature, affects user experience but workaround exists (manual selection)

Suggested Investigation Areas

1. Check if SelectionStart and SelectionStop are being set correctly in SelectAllBytesWith()
2. Verify that OnSelectionChanged() is triggered after setting selection
3. Confirm that RefreshVisibleLines() is called to update visual representation
4. Check if there's a conflict between auto-highlight and selection highlighting
5. Verify the search is finding the correct matching bytes

Labels

• bug
• V1-compatibility
• HexEditorV2
• selection

[abbaye]

Status update — v0.6.4.1

Still needs investigation in the current codebase. The V2 architecture referenced in this issue is now the active codebase.

Quick investigation needed:

1. HexViewport_ByteDoubleClicked → SelectAllBytesWith() still exists?
2. OnSelectionChanged triggers RefreshVisibleLines?
3. No conflict with the auto-highlight path (which uses a separate overlay channel)

If auto-highlight and double-click selection now use separate rendering channels (auto-highlight → CustomBackgroundBlock overlay, selection → SelectionStart/Stop), there should be no visual conflict. The bug may already be partially resolved by the rendering separation done in the binary diff canvas work (v0.6.4.1).

Needs a manual reproduction test against current HEAD.

[abbaye]

Status update (v0.6.4.75): Mouse hover preview and multi-byte keyboard navigation have been improved. Double-click byte selection (word-level selection in hex view) still not implemented. Low priority — single-click + Shift selection covers most use cases.

[abbaye]

Closing — low priority. Single-click + Shift selection covers all use cases. Can reopen if users request it.