fix selection and cursor

src/main.cpp

@@ -131,7 +131,10 @@ void win32_show_cursor(bool visible)
 {
     std::lock_guard<std::mutex> lock(main_task_mutex);
     main_tasklist.emplace_back([=] {
-        ShowCursor(visible);
+        if (visible)
+            while (ShowCursor(true) < 0);
+        else
+            while (ShowCursor(false) >= 0);
     });
 }