JBR-1795 Project opened from Welcome screen goes to backgound after loading

(cherry picked from commit 322526458a)

src/java.desktop/windows/native/libawt/windows/awt_Frame.cpp

@@ -786,6 +786,24 @@ AwtFrame::Show()
         } else {
             ::ShowWindow(hwnd, SW_SHOWMAXIMIZED);
         }
+
+        // [tav] Workaround for unclear platform behaviour.
+        // When a custom decor frame is being shown maximized at the moment
+        // some another AWT window is still foreground - the frame can go
+        // in background when shown if:
+        // 1) the other AWT window is closed the moment after frame's show
+        // 2) some another maximized window is behind the frame, it steals activation
+        if (HasCustomDecoration()) {
+            HWND fgHWnd = ::GetForegroundWindow();
+            if (fgHWnd != NULL &&
+                GetComponent(fgHWnd) != NULL && // it's awt window
+                IsFocusableWindow() &&
+                IsAutoRequestFocus() &&
+                !::IsWindow(GetModalBlocker(GetHWnd())))
+            {
+                ::SetForegroundWindow(GetHWnd());
+            }
+        }
     }
     else if (m_isInputMethodWindow) {
         // Don't activate input methow window