Win32: Fix no Super key release event after Win+V

The Win+V hotkey brings up a clipboard history IME that consumes the key
release.  This adds left and right Super to the modifier keys manually
polled for undetected release during event processing.

Fixes #1622.

README.md

@@ -141,6 +141,7 @@ information on what to include when reporting a bug.
  - [Win32] Bugfix: The window hint `GLFW_MAXIMIZED` did not move or resize the
    window (#1499)
  - [Win32] Bugfix: Disabled cursor mode interfered with some non-client actions
+ - [Win32] Bugfix: Super key was not released after Win+V hotkey (#1622)
  - [Cocoa] Added support for `VK_EXT_metal_surface` (#1619)
  - [Cocoa] Added locating the Vulkan loader at runtime in an application bundle
  - [Cocoa] Removed dependency on the CoreVideo framework

src/win32_window.c

@@ -1934,30 +1934,39 @@ void _glfwPlatformPollEvents(void)
         }
     }
 
+    // HACK: Release modifier keys that the system did not emit KEYUP for
+    // NOTE: Shift keys on Windows tend to "stick" when both are pressed as
+    //       no key up message is generated by the first key release
+    // NOTE: Windows key is not reported as released by the Win+V hotkey
+    //       Other Win hotkeys are handled implicitly by _glfwInputWindowFocus
+    //       because they change the input focus
     handle = GetActiveWindow();
     if (handle)
     {
-        // NOTE: Shift keys on Windows tend to "stick" when both are pressed as
-        //       no key up message is generated by the first key release
-        //       The other half of this is in the handling of WM_KEYUP
-        // HACK: Query actual key state and synthesize release events as needed
         window = GetPropW(handle, L"GLFW");
         if (window)
         {
-            const GLFWbool lshift = (GetAsyncKeyState(VK_LSHIFT) & 0x8000) != 0;
-            const GLFWbool rshift = (GetAsyncKeyState(VK_RSHIFT) & 0x8000) != 0;
-
-            if (!lshift && window->keys[GLFW_KEY_LEFT_SHIFT] == GLFW_PRESS)
+            int i;
+            const int keys[4][2] =
             {
-                const int mods = getAsyncKeyMods();
-                const int scancode = _glfw.win32.scancodes[GLFW_KEY_LEFT_SHIFT];
-                _glfwInputKey(window, GLFW_KEY_LEFT_SHIFT, scancode, GLFW_RELEASE, mods);
-            }
-            else if (!rshift && window->keys[GLFW_KEY_RIGHT_SHIFT] == GLFW_PRESS)
+                { VK_LSHIFT, GLFW_KEY_LEFT_SHIFT },
+                { VK_RSHIFT, GLFW_KEY_RIGHT_SHIFT },
+                { VK_LWIN, GLFW_KEY_LEFT_SUPER },
+                { VK_RWIN, GLFW_KEY_RIGHT_SUPER }
+            };
+
+            for (i = 0;  i < 4;  i++)
             {
-                const int mods = getAsyncKeyMods();
-                const int scancode = _glfw.win32.scancodes[GLFW_KEY_RIGHT_SHIFT];
-                _glfwInputKey(window, GLFW_KEY_RIGHT_SHIFT, scancode, GLFW_RELEASE, mods);
+                const int vk = keys[i][0];
+                const int key = keys[i][1];
+                const int scancode = _glfw.win32.scancodes[key];
+
+                if ((GetAsyncKeyState(vk) & 0x8000))
+                    continue;
+                if (window->keys[key] != GLFW_PRESS)
+                    continue;
+
+                _glfwInputKey(window, key, scancode, GLFW_RELEASE, getAsyncKeyMods());
             }
         }
     }