[BUG] File cannot be attached to chat

[ryanleung96]

Problem (one or two sentences)

Text files cannot be added to chat with drag method.

Context (who is affected and when)

Happens in newest version on every chat mode.

Reproduction steps

1. Press shift to start dragging a text file from my PC
2. Place the text file to input box.
3. No text file was attached.

Mango.Recorder-29-04-2026-12-11-00.mp4

Expected result

Text file attached successfully

Actual result

No file was attached

Variations tried (optional)

No response

App Version

v3.53.0 (44f6bba)

API Provider (optional)

OpenAI Compatible

Model Used (optional)

No response

Roo Code Task Links (optional)

No response

Relevant logs or errors (optional)

[roomote-v0]

I've analyzed this issue and here's my proposed implementation plan:

Root cause: In ChatTextArea.tsx, the handleDrop function has two code paths for dropped content. When files are dragged from the OS file manager (not from VSCode's file explorer), they end up in e.dataTransfer.files. However, only image files (png, jpeg, webp) are processed from that collection -- non-image files like .txt are silently ignored.

Proposed fix:

1. In the handleDrop callback in webview-ui/src/components/chat/ChatTextArea.tsx, after processing image files from e.dataTransfer.files, add handling for non-image files
2. For non-image files, use the Electron-provided File.path property (which contains the full filesystem path for files dragged from the OS) to convert the file path into an @/ mention using the existing convertToMentionPath utility
3. Insert the resulting mention(s) into the chat input, similar to how text/URI-based file drops already work (lines 824-852)
4. Add corresponding tests in ChatTextArea.spec.tsx to cover this new behavior

This approach reuses the existing mention infrastructure and keeps the behavior consistent: whether files are dragged from VSCode's file explorer or from the OS file manager, they get converted to @/ file mentions in the chat input.

Please mention @roomote in a comment saying that you approve this plan, and I'll proceed with the implementation.