[NUI] When hiding the overlaid border, the timer is also initialized.

If the timer is not initialized, the border will not be visible when OverlayBorderShoew is performed again while the timer is alive.

diff --git a/src/Tizen.NUI/src/public/Window/DefaultBorder.cs b/src/Tizen.NUI/src/public/Window/DefaultBorder.cs
index 200f4c6..672f5f1 100755 (executable)
--- a/src/Tizen.NUI/src/public/Window/DefaultBorder.cs
+++ b/src/Tizen.NUI/src/public/Window/DefaultBorder.cs
@@ -879,6 +879,9 @@ namespace Tizen.NUI
             if (BorderWindow != null && BorderWindow.IsMaximized())
             {
                 borderView?.Hide();
+                overlayTimer?.Stop();
+                overlayTimer?.Dispose();
+                overlayTimer = null;
                 return true;
             }
             return false;