Win32: Fix fullscreen errors using Taskbar system menu

Changing window state using taskbar system menu could result in a titleless window.

Differential Revision: https://developer.blender.org/D10812

Reviewed by Ray Molenkamp

2 files changed, 15 insertions, 4 deletions

diff --git a/intern/ghost/intern/GHOST_SystemWin32.cpp b/intern/ghost/intern/GHOST_SystemWin32.cpp
index 430e8216ae3..38dea9c1142 100644
--- a/intern/ghost/intern/GHOST_SystemWin32.cpp
+++ b/intern/ghost/intern/GHOST_SystemWin32.cpp
@@ -1442,12 +1442,23 @@ LRESULT WINAPI GHOST_SystemWin32::s_wndProc(HWND hwnd, UINT msg, WPARAM wParam,
            */
           break;
         case WM_SYSCOMMAND:
-          /* The WM_SYSCHAR message is sent to the window when system commands such as
+          /* The WM_SYSCOMMAND message is sent to the window when system commands such as
            * maximize, minimize  or close the window are triggered. Also it is sent when ALT
            * button is press for menu. To prevent this we must return preventing DefWindowProc.
+           *
+           * Note that the four low-order bits of the wParam parameter are used internally by the
+           * OS. To obtain the correct result when testing the value of wParam, an application
+           * must combine the value 0xFFF0 with the wParam value by using the bitwise AND operator.
            */
-          if (wParam == SC_KEYMENU) {
-            eventHandled = true;
+          switch (wParam & 0xFFF0) {
+            case SC_KEYMENU:
+              eventHandled = true;
+              break;
+            case SC_RESTORE:
+              ::ShowWindow(hwnd, SW_RESTORE);
+              window->setState(window->getState());
+              eventHandled = true;
+              break;
           }
           break;
         ////////////////////////////////////////////////////////////////////////
diff --git a/intern/ghost/intern/GHOST_WindowWin32.cpp b/intern/ghost/intern/GHOST_WindowWin32.cpp
index 28ce1381562..ef155d96f99 100644
--- a/intern/ghost/intern/GHOST_WindowWin32.cpp
+++ b/intern/ghost/intern/GHOST_WindowWin32.cpp
@@ -521,7 +521,7 @@ GHOST_TSuccess GHOST_WindowWin32::setState(GHOST_TWindowState state)
 
   switch (state) {
     case GHOST_kWindowStateMinimized:
-      wp.showCmd = SW_SHOWMINIMIZED;
+      wp.showCmd = SW_MINIMIZE;
       break;
     case GHOST_kWindowStateMaximized:
       wp.showCmd = SW_SHOWMAXIMIZED;