Windows: HWnd::create_timer leaks an extra thread timer #362

Environment

baseview 0.4.1 on Windows.

Problem

In src/wrappers/win32/window/handle.rs, HWnd::create_timer() calls SetTimer(NULL, 0, ...) to obtain an ID, then reset_timer() calls SetTimer(hwnd, id, ...).

These are two separate timers. kill_timer() calls KillTimer(hwnd, id), which stops only the window-owned timer. The original thread timer remains active, including after the window is destroyed. It also leaks if reset_timer() fails.

The SetTimer documentation states that timer identifiers are specific to the associated window. KillTimer requires the same HWND used for creation, including NULL for thread timers.

Repeated timer creation and cancellation therefore accumulates orphaned thread timers.

Observed impact

With continuous redraws, the UI became progressively choppy and froze after several minutes, including while idle. Closing and reopening the window could leave it black.

Fix applied locally

Removed the initial SetTimer(NULL, 0, ...) call and instead allocated unique, nonzero IDs using an overflow-checked atomic counter. create_timer() then creates only the window-owned timer through the existing reset_timer().

reset_timer() and kill_timer() remain unchanged. Creation, reset, and cancellation now use the same HWND/ID pair, and window destruction cleans up the timer. The counter cannot wrap and reuse live IDs.

With the local fix applied, the Windows UI remained open for approximately 30 minutes without freezing or progressive slowdown and stayed fast and responsive.