[0.4.14][NTUSER] Allow Window Snap to be disabled and optimize

Win+Left, Win+Right, Win+Up, and Win+Down can be disabled by registry value WindowArrangementActive REG_SZ 0 in
HKEY_CURRENT_USER\Control Panel\Desktop
Snapping mouse can be also disabled.

by porting back:
0.4.15-dev-5703-g d04e148d1c Optimize window snap disabling (#5061)
0.4.15-dev-5641-g ea55101aad Allow Window Snap to be disabled (#5014) CORE-16379 (#5014)

Also port back some minor unrelated improvements:
0.4.15-dev-3341-g 4bc95812fd defwnd.c Mark default as unreachable.
0.4.15-dev-316-g 938df97b54 nonclient.c NC_IconForWindow(): Remove redundant if() (#2842)
and:
-defwnd.c: delete a malformed TRACE() which had a format string, but no argument.

win32ss/user/ntuser/defwnd.c

@@ -414,7 +414,6 @@ UserPaintCaption(PWND pWnd, INT Flags)
          * RealUserDrawCaption in order to draw the classic caption when themes
          * are disabled but the themes service is enabled
          */
-         TRACE("UDCB Flags %08x\n");
          co_IntSendMessage(UserHMGetHandle(pWnd), WM_NCUAHDRAWCAPTION, Flags, 0);
       }
       else
@@ -486,8 +485,7 @@ DefWndGetIcon(PWND pWnd, WPARAM wParam, LPARAM lParam)
         case ICON_SMALL2:
             hIconRet = UserGetProp(pWnd, gpsi->atomIconSmProp, TRUE);
             break;
-        default:
+        DEFAULT_UNREACHABLE;
-            break;
     }
     return (LRESULT)hIconRet;
 }
@@ -539,9 +537,6 @@ IntDefWindowProc(
    PTHREADINFO pti = PsGetCurrentThreadWin32Thread();
    LRESULT lResult = 0;
    USER_REFERENCE_ENTRY Ref;
-   BOOL IsTaskBar;
-   DWORD Style;
-   DWORD ExStyle;
 
    if (Msg > WM_USER) return 0;
 
@@ -787,31 +782,26 @@ IntDefWindowProc(
                co_IntSendMessage(UserHMGetHandle(Wnd), WM_CONTEXTMENU, (WPARAM)UserHMGetHandle(Wnd), MAKELPARAM(-1, -1));
             }
          }
-         if (IS_KEY_DOWN(gafAsyncKeyState, VK_LWIN) || IS_KEY_DOWN(gafAsyncKeyState, VK_RWIN))
+         if (g_bWindowSnapEnabled && (IS_KEY_DOWN(gafAsyncKeyState, VK_LWIN) || IS_KEY_DOWN(gafAsyncKeyState, VK_RWIN)))
          {
+            BOOL IsTaskBar;
+            DWORD StyleTB;
+            DWORD ExStyleTB;
             HWND hwndTop = UserGetForegroundWindow();
             PWND topWnd = UserGetWindowObject(hwndTop);
 
-            /* Test for typical TaskBar ExStyle Values */
+            // We want to forbid snapping operations on the TaskBar
-            ExStyle = (topWnd->ExStyle & WS_EX_TOOLWINDOW);
+            // We use a heuristic for detecting the TaskBar Wnd by its typical Style & ExStyle Values
-            TRACE("ExStyle is '%x'.\n", ExStyle);
+            ExStyleTB = (topWnd->ExStyle & WS_EX_TOOLWINDOW);
+            StyleTB = (topWnd->style & (WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN));
+            IsTaskBar = (StyleTB == (WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN))
+                        && (ExStyleTB == WS_EX_TOOLWINDOW);
+            TRACE("ExStyle=%x Style=%x IsTaskBar=%d\n", ExStyleTB, StyleTB, IsTaskBar);
 
-            /* Test for typical TaskBar Style Values */
+            if (topWnd && !IsTaskBar)
-            Style = (topWnd->style & (WS_POPUP | WS_VISIBLE |
-                        WS_CLIPSIBLINGS | WS_CLIPCHILDREN));
-            TRACE("Style is '%x'.\n", Style);
-
-            /* Test for masked typical TaskBar Style and ExStyles to detect TaskBar */
-            IsTaskBar = (Style == (WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN))
-                        && (ExStyle == WS_EX_TOOLWINDOW);
-            TRACE("This %s the TaskBar.\n", IsTaskBar ? "is" : "is not");
-
-            if (topWnd && !IsTaskBar)  /* Second test is so we are not touching the Taskbar */
             {
                if ((topWnd->style & WS_THICKFRAME) == 0)
-               {
                   return 0;
-               }
 
                if (wParam == VK_DOWN)
                {

win32ss/user/ntuser/nonclient.c

@@ -256,8 +256,6 @@ DefWndDoSizeMove(PWND pwnd, WORD wParam)
    //PMONITOR mon = 0; Don't port sync from wine!!! This breaks explorer task bar sizing!!
    //                  The task bar can grow in size and can not reduce due to the change
    //                  in the work area.
-   DWORD ExStyleTB, StyleTB;
-   BOOL IsTaskBar;
 
    Style = pwnd->style;
    ExStyle = pwnd->ExStyle;
@@ -393,35 +391,33 @@ DefWndDoSizeMove(PWND pwnd, WORD wParam)
       if (!co_IntGetPeekMessage(&msg, 0, 0, 0, PM_REMOVE, TRUE)) break;
       if (IntCallMsgFilter( &msg, MSGF_SIZE )) continue;
 
-      /* Exit on button-up */
+      if (msg.message == WM_KEYDOWN && (msg.wParam == VK_RETURN || msg.wParam == VK_ESCAPE))
-      if (msg.message == WM_LBUTTONUP)
+         break; // Exit on Return or Esc
-      {
+
-         /* Test for typical TaskBar ExStyle Values */
+      if (!g_bWindowSnapEnabled && (msg.message == WM_LBUTTONUP))
+      { // If no WindowSnapEnabled: Exit on button-up immediately
+         break;
+      }
+      else if (g_bWindowSnapEnabled && msg.message == WM_LBUTTONUP)
+      { // If WindowSnapEnabled: Decide whether to snap before exiting
+         DWORD ExStyleTB, StyleTB;
+         BOOL IsTaskBar;
+
+         // We want to forbid snapping operations on the TaskBar
+         // We use a heuristic for detecting the TaskBar Wnd by its typical Style & ExStyle Values
          ExStyleTB = (ExStyle & WS_EX_TOOLWINDOW);
-         TRACE("ExStyle is '%x'.\n", ExStyleTB);
+         StyleTB = (Style & (WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN));
-
-         /* Test for typical TaskBar Style Values */
-         StyleTB = (Style & (WS_POPUP | WS_VISIBLE |
-                        WS_CLIPSIBLINGS | WS_CLIPCHILDREN));
-         TRACE("Style is '%x'.\n", StyleTB);
-
-         /* Test for masked typical TaskBar Style and ExStyles to detect TaskBar */
          IsTaskBar = (StyleTB == (WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN))
                      && (ExStyleTB == WS_EX_TOOLWINDOW);
-         TRACE("This %s the TaskBar.\n", IsTaskBar ? "is" : "is not");
+         TRACE("ExStyle=%x Style=%x IsTaskBar=%d\n", ExStyleTB, StyleTB, IsTaskBar);
 
          // check for snapping if was moved by caption
-         if (hittest == HTCAPTION && thickframe && (ExStyle & WS_EX_MDICHILD) == 0)
+         if (!IsTaskBar && hittest == HTCAPTION && thickframe && (ExStyle & WS_EX_MDICHILD) == 0)
          {
             RECT snapRect;
             BOOL doSideSnap = FALSE;
             UserSystemParametersInfo(SPI_GETWORKAREA, 0, &snapRect, 0);
 
-            /* if this is the taskbar, then we want to just exit */
-            if (IsTaskBar)
-            {
-               break;
-            }
             // snap to left
             if (pt.x <= snapRect.left)
             {
@@ -459,13 +455,6 @@ DefWndDoSizeMove(PWND pwnd, WORD wParam)
          break;
       }
 
-      /* Exit on Return or Esc */
-      if (msg.message == WM_KEYDOWN &&
-          (msg.wParam == VK_RETURN || msg.wParam == VK_ESCAPE))
-      {
-         break;
-      }
-
       if ((msg.message != WM_KEYDOWN) && (msg.message != WM_MOUSEMOVE))
       {
          IntTranslateKbdMessage( &msg , 0 );
@@ -696,7 +685,7 @@ PCURICON_OBJECT FASTCALL NC_IconForWindow( PWND pWnd )
    // it does not use the default icon! And it does not check for DS_MODALFRAME.
    if (!hIcon && !(pWnd->ExStyle & WS_EX_DLGMODALFRAME))
    {
-      if (!hIcon) hIcon = gpsi->hIconSmWindows; // Both are IDI_WINLOGO Small
+      hIcon = gpsi->hIconSmWindows; // Both are IDI_WINLOGO Small
       if (!hIcon) hIcon = gpsi->hIconWindows;   // Reg size.
    }
    if (hIcon)

win32ss/user/ntuser/sysparams.c

@@ -17,6 +17,7 @@ DBG_DEFAULT_CHANNEL(UserSysparams);
 SPIVALUES gspv;
 BOOL gbSpiInitialized = FALSE;
 BOOL g_PaintDesktopVersion = FALSE;
+BOOL g_bWindowSnapEnabled = TRUE;
 
 // HACK! We initialize SPI before we have a proper surface to get this from.
 #define dpi 96
@@ -99,8 +100,6 @@ static const WCHAR* KEY_KDBPREF = L"Control Panel\\Accessibility\\Keyboard Prefe
 static const WCHAR* KEY_SCRREAD = L"Control Panel\\Accessibility\\Blind Access";
 static const WCHAR* VAL_ON = L"On";
 
-
-
 /** Loading the settings ******************************************************/
 
 static
@@ -214,6 +213,18 @@ SpiFixupValues(VOID)
 
 }
 
+static BOOL IntIsWindowSnapEnabled(VOID)
+{
+    WCHAR szValue[2];
+    if (RegReadUserSetting(L"Control Panel\\Desktop", L"WindowArrangementActive",
+                           REG_SZ, szValue, sizeof(szValue)))
+    {
+        szValue[RTL_NUMBER_OF(szValue) - 1] = UNICODE_NULL; /* Avoid buffer overrun */
+        return (_wtoi(szValue) != 0);
+    }
+    return TRUE;
+}
+
 static
 VOID
 SpiUpdatePerUserSystemParameters(VOID)
@@ -342,6 +353,8 @@ SpiUpdatePerUserSystemParameters(VOID)
        if (SPITESTPREF(UPM_LISTBOXSMOOTHSCROLLING)) gpsi->PUSIFlags |= PUSIF_LISTBOXSMOOTHSCROLLING;
     }
     gdwLanguageToggleKey = UserGetLanguageToggle();
+
+    g_bWindowSnapEnabled = IntIsWindowSnapEnabled();
 }
 
 BOOL

win32ss/user/ntuser/window.h

@@ -4,6 +4,7 @@ extern ATOM AtomMessage;
 extern ATOM AtomWndObj; /* WNDOBJ list */
 extern ATOM AtomLayer;
 extern ATOM AtomFlashWndState;
+extern BOOL g_bWindowSnapEnabled;
 
 #define HAS_DLGFRAME(Style, ExStyle) \
             (((ExStyle) & WS_EX_DLGMODALFRAME) || \