winex11.drv: Preserve last error in x11drv_thread_data().

dlls/user32/dialog.c

@@ -283,6 +283,7 @@ static BOOL DIALOG_CreateControls32( HWND hwnd, LPCSTR template, const DLG_TEMPL
             WARN("control %s %s creation failed\n", debugstr_w(info.className),
                  debugstr_w(info.windowName));
             if (dlgTemplate->style & DS_NOFAILCREATE) continue;
+            SetLastError(0);
             return FALSE;
         }
 

dlls/user32/menu.c

@@ -3518,6 +3518,7 @@ BOOL WINAPI TrackPopupMenuEx( HMENU hMenu, UINT wFlags, INT x, INT y,
                SendMessageW( hWnd, WM_UNINITMENUPOPUP, (WPARAM)hMenu,
                              MAKELPARAM(0, IS_SYSTEM_MENU(menu)) );
         }
+        SetLastError(0);
     }
 
     return ret;

dlls/user32/tests/input.c

@@ -1928,8 +1928,17 @@ static void test_Input_mouse(void)
     DWORD thread_id;
     POINT pt, pt_org;
     MSG msg;
+    BOOL ret;
 
-    GetCursorPos(&pt_org);
+    SetLastError(0xdeadbeef);
+    ret = GetCursorPos(NULL);
+    ok(!ret, "GetCursorPos succeed\n");
+    ok(GetLastError() == 0xdeadbeef || GetLastError() == ERROR_NOACCESS, "error %u\n", GetLastError());
+
+    SetLastError(0xdeadbeef);
+    ret = GetCursorPos(&pt_org);
+    ok(ret, "GetCursorPos failed\n");
+    ok(GetLastError() == 0xdeadbeef, "error %u\n", GetLastError());
 
     button_win = CreateWindowA("button", "button", WS_VISIBLE | WS_POPUP,
             100, 100, 100, 100, 0, NULL, NULL, NULL);

dlls/user32/tests/win.c

@@ -6261,6 +6261,14 @@ static void test_CreateWindow(void)
     ok( rc.bottom <= expected_cy, "invalid rect bottom %u\n", rc.bottom );
     DestroyWindow(hwnd);
 
+    /* invalid class */
+    SetLastError(0xdeadbeef);
+    hwnd = CreateWindowExA(0, "INVALID_CLASS", NULL, WS_CHILD, 10, 10, 100, 100, parent, 0, 0, NULL);
+    ok(hwnd == 0, "CreateWindowEx succeeded\n");
+    ok(GetLastError() == ERROR_CLASS_DOES_NOT_EXIST || GetLastError() == ERROR_CANNOT_FIND_WND_CLASS,
+        "invalid error %u\n", GetLastError());
+    DestroyWindow(hwnd);
+
     if (pGetLayout && pSetLayout)
     {
         HDC hdc = GetDC( parent );

dlls/winex11.drv/x11drv.h

@@ -345,7 +345,10 @@ extern DWORD thread_data_tls_index DECLSPEC_HIDDEN;
 
 static inline struct x11drv_thread_data *x11drv_thread_data(void)
 {
-    return TlsGetValue( thread_data_tls_index );
+    DWORD err = GetLastError();  /* TlsGetValue always resets last error */
+    struct x11drv_thread_data *data = TlsGetValue( thread_data_tls_index );
+    SetLastError( err );
+    return data;
 }
 
 /* retrieve the thread display, or NULL if not created yet */