Resolves: tdf#143795 trigger layout when content changes

Change-Id: I9ec19b55f2b46ac8dd1415f45d5e0368fa52fbfd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/120367
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/sd/source/ui/sidebar/SlideBackground.cxx b/sd/source/ui/sidebar/SlideBackground.cxx
index 28c560f..efb397c 100644
--- a/sd/source/ui/sidebar/SlideBackground.cxx
+++ b/sd/source/ui/sidebar/SlideBackground.cxx
@@ -451,6 +451,11 @@ void SlideBackground::Update()
        default:
            break;
    }

    // Need to do a relayouting, otherwise the panel size is not updated after show / hide controls
    sfx2::sidebar::Panel* pPanel = dynamic_cast<sfx2::sidebar::Panel*>(GetParent());
    if (pPanel)
        pPanel->TriggerDeckLayouting();
}

void SlideBackground::UpdateMarginBox()