On Windows, set the cursor icon when the cursor first enters a window (#1807)

CHANGELOG.md

@@ -1,5 +1,6 @@
 # Unreleased
 
+- On Windows, fix bug causing newly created windows to erroneously display the "wait" (spinning) cursor.
 - On Windows, change the default window size (1024x768) to match the default on other desktop platforms (800x600).
 - On Windows, fix bug causing mouse capture to not be released.
 - On Windows, fix fullscreen not preserving minimized/maximized state.

src/platform_impl/windows/event_loop.rs

@@ -20,7 +20,7 @@ use winapi::shared::basetsd::{DWORD_PTR, UINT_PTR};
 
 use winapi::{
     shared::{
-        minwindef::{BOOL, DWORD, HIWORD, INT, LOWORD, LPARAM, LRESULT, UINT, WPARAM},
+        minwindef::{BOOL, DWORD, HIWORD, INT, LOWORD, LPARAM, LRESULT, UINT, WORD, WPARAM},
         windef::{HWND, POINT, RECT},
         windowsx, winerror,
     },
@@ -1664,11 +1664,11 @@ unsafe fn public_window_callback_inner<T: 'static>(
         winuser::WM_SETCURSOR => {
             let set_cursor_to = {
                 let window_state = subclass_input.window_state.lock();
-                if window_state
-                    .mouse
-                    .cursor_flags()
-                    .contains(CursorFlags::IN_WINDOW)
-                {
+                // The return value for the preceding `WM_NCHITTEST` message is conveniently
+                // provided through the low-order word of lParam. We use that here since
+                // `WM_MOUSEMOVE` seems to come after `WM_SETCURSOR` for a given cursor movement.
+                let in_client_area = LOWORD(lparam as DWORD) == winuser::HTCLIENT as WORD;
+                if in_client_area {
                     Some(window_state.mouse.cursor)
                 } else {
                     None