[Bug] Cursor jumps to bottom when editing large messages mid-text

Bug Description
When typing a very long message and pasting text at the bottom, then trying to move the cursor back up to edit text earlier in the message, the cursor dissapears offscreen. I can scroll up with the mouse but when I type the window immediately jumps back down to the bottom. This makes it impossible to edit large messages as the window jumps away from the content I am typing on every keystroke.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.27
• Feedback ID: 24c94f42-5c7a-4c8e-8a3b-645e7206e673

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/aferraro/.local/share/claude/versions/2.1.27 (expected in multi-process scenarios)\n    at DUR (/$bunfs/root/claude:3589:2098)\n    at jPA (/$bunfs/root/claude:3589:1209)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-31T18:51:59.150Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readFileSync (unknown)\n    at <anonymous> (/$bunfs/root/claude:12:742)\n    at yC (/$bunfs/root/claude:11:40705)\n    at readFileSync (/$bunfs/root/claude:12:701)\n    at AVB (/$bunfs/root/claude:5141:20088)\n    at call (/$bunfs/root/claude:3532:1451)\n    at call (/$bunfs/root/claude:3528:7071)\n    at ND8 (/$bunfs/root/claude:3059:12903)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-31T18:56:22.906Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"thinking.enabled.budget_tokens: Input should be greater than or equal to 1024\"},\"request_id\":\"req_011CXfywjRC54A4yqzKy62vn\"}\n    at generate (/$bunfs/root/claude:343:8698)\n    at makeRequest (/$bunfs/root/claude:360:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-31T19:09:03.369Z"}]