Bug / UX Issue: Incomplete deletion when removing tool calls from the timeline

[VooDisss]

Bug / UX Issue: Incomplete deletion when removing tool calls from the timeline

Problem

When users select specific tool calls from the timeline for bulk deletion (instead of selecting an entire message), the deletion process only removes the tool call parts. The associated "reasoning" block (thinking tokens) and "text" parts generated based on that tool output are left behind.

Additionally, the red pre-deletion overlay only highlights the tool call cards. It does not visually indicate that any other associated components (like the message header, reasoning, or text) are part of the context being managed.

Impact

• Orphaned Content: Deleting a tool call leaves behind an incomplete message structure—an assistant response with "thinking" and "text" but no underlying tool call output.
• Misleading Visuals: The UI fails to clearly communicate what parts of the message belong to the selected tool calls, making the delete action feel unpredictable and preventing users from cleaning up their conversation history accurately.

Expected Behavior

1. Aggressive Companion-Part Deletion: When tool parts of a message are selected for deletion, the deletion action should also automatically remove the corresponding step-finish, reasoning, and text parts associated with that message. The chat history should be cleanly purged of all content tied to those tools.
2. Extended Delete Overlays: When a user selects tool calls for deletion, the red destructive overlay should extend to the message headers, reasoning cards (thinking tokens), and text parts to accurately reflect the scope of what will be removed.

[pascalandr]

#247 (comment)