Inline Breakpoint Indicators Not Activating on Hover/Click

Bug Reports
1

Description:
When using a debug adapter that supports inline breakpoints, Cursor correctly displays the valid breakpoint indicators (dots) on a line. However, hovering over these indicators does not cause them to become active (e.g., turn red or show a clickable state), and clicking on them does not trigger any action. In contrast, Visual Studio Code properly activates and handles these interactions, setting column-specific breakpoints.

Steps to Reproduce:

  1. Use a debug adapter that declares supportsBreakpointLocationsRequest: true and supports inline breakpoints.
  2. Open a file in the Cursor editor.
  3. Observe that valid breakpoint positions are visually indicated.
  4. Hover over one of the inline dots; note that it does not become active or change appearance.
  5. Click on a grey dot; observe that no column-specific breakpoint is set (logs for setBreakpoints confirm that the method is not called).

Expected Behavior:
Hovering over an inline breakpoint indicator should activate it (e.g., change its color to red), and clicking the indicator should capture the exact column where the user clicked and send a setBreakpoints request to the debug adapter with both the line number and the column information.

Actual Behavior:
While Cursor successfully queries and displays the valid breakpoint locations, it fails to handle hover and click events on the indicators. As a result, no column-specific breakpoint is set, and the UI does not reflect any interactive state.

Technical Analysis:

  • Breakpoint Location Query:
    Cursor correctly requests and receives valid breakpoint positions from the debug adapter.
  • UI Rendering:
    The inline breakpoint indicators (dots) are displayed as expected; however, they do not become active on hover, which suggests missing or incomplete event handling.
  • Comparison with VSCode:
    Visual Studio Code implements the interaction layer correctly by activating the indicator on hover and translating user clicks into column-specific breakpoint requests.

Environment:

  • Cursor Editor (latest build)
  • macOS 14.0

Potential Fix Suggestions:

  1. Implement Event Handlers:
    Add event listeners to the inline breakpoint indicators to capture both the line and the precise column when the user hovers or clicks.
  2. Update Request Logic:
    Modify the event handlers to visually activate the indicator on hover and to construct and send a setBreakpoints request that includes the captured column data when clicked.
  3. Reference VSCode Implementation:
    Review how Visual Studio Code handles inline breakpoint events (e.g., in files like debugEditorContribution.ts) and adapt a similar solution in Cursor’s codebase.

Additional Information:
This issue appears to be isolated to Cursor’s implementation of the Debug Adapter Protocol (DAP) for inline breakpoints.