[WIP] Fix mouse move event handling in XI_MOTION implementation

[Copilot]

Fix XI_Motion Event Handling for Both Scroll and Mouse Motion

Problem Analysis

The current XI_Motion handler only processes scroll events and ignores regular mouse motion events, causing cursor movement to break when smooth scrolling is enabled.

Plan

• Analyze the codebase and locate XI_Motion event handling in glfw/x11_window.c
• Understand the issue: XI_Motion events override legacy MotionNotify when selected, but current handler only processes scroll events
• Modify XI_Motion handler to process both scroll events AND regular mouse motion
• Test that mouse cursor movement works correctly
• Test that scroll events continue to work correctly
• Verify no regressions in mouse handling

Technical Details

• File: glfw/x11_window.c, lines 1336-1388
• Current handler only processes events when scroll device is found
• Need to add fallback to handle regular mouse motion using XIDeviceEvent position fields (event_x, event_y)

Original prompt

Problem

The current code has handling for scroll events via XI_MOTION, but this implementation breaks mouse move event handling. Both types of motion events need to be properly handled without interfering with each other.

Requirements

1. Investigate the current XI_MOTION implementation: Find where XI_MOTION events are currently being handled for scroll events in the codebase (likely in X11-related input handling code).

2. Fix the mouse motion event handling: The existing XI_MOTION scroll event handling is breaking mouse move events. Modify the code to properly differentiate between:

   • Scroll events (wheel/touchpad scrolling)
   • Mouse motion events (cursor movement)

3. Ensure both event types work correctly:

   • Mouse motion events should update cursor position
   • Scroll events should continue to work as they currently do
   • One should not interfere with the other

Technical Context

• This is related to XInput2 (XI2) event handling on X11
• The XI_MOTION event type can represent different kinds of motion (mouse movement, scroll wheel, etc.)
• The fix likely needs to check valuator data or event masks to distinguish between scroll and mouse motion
• Look for code patterns that check for scroll valuators vs position valuators

Expected Outcome

After this fix:

• Mouse cursor movement should work properly in kitty
• Scroll events (both mouse wheel and touchpad) should continue to work
• Both event types should be handled correctly through the XI_MOTION event path

This pull request was created from Copilot chat.

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