Support stylesheets in drop site widget

src/blackgui/dockwidget.cpp

@@ -442,6 +442,7 @@ namespace BlackGui
 
     void CDockWidget::ps_onStyleSheetsChanged()
     {
+        // style sheet changes go here
     }
 
     void CDockWidget::forceStyleSheetUpdate()

src/blackgui/dropsite.cpp

@@ -8,6 +8,7 @@
  */
 
 #include "dropsite.h"
+#include "stylesheetutility.h"
 #include <QDragEnterEvent>
 
 using namespace BlackMisc;
@@ -20,6 +21,8 @@ namespace BlackGui
         setAlignment(Qt::AlignCenter);
         setAcceptDrops(true);
         this->setInfoText(tr("<drop content>"));
+        connect(&CStyleSheetUtility::instance(), &CStyleSheetUtility::styleSheetsChanged, this, &CDropSite::ps_onStyleSheetsChanged);
+        this->ps_onStyleSheetsChanged();
     }
 
     void CDropSite::setInfoText(const QString &dropSiteText)
@@ -72,4 +75,15 @@ namespace BlackGui
         this->resetText();
     }
 
+    void CDropSite::ps_onStyleSheetsChanged()
+    {
+        // style sheet changes go here
+    }
+
+    void CDropSite::paintEvent(QPaintEvent *event)
+    {
+        CStyleSheetUtility::useStyleSheetInDerivedWidget(this, QStyle::PE_FrameDockWidget);
+        QLabel::paintEvent(event);
+    }
+
 } // ns

src/blackgui/dropsite.h

@@ -54,6 +54,13 @@ namespace BlackGui
         //! \copydoc QWidget::dropEvent
         virtual void dropEvent(QDropEvent *event) override;
 
+        //! \copydoc QWidget::paintEvent
+        virtual void paintEvent(QPaintEvent *event) override;
+
+    private slots:
+        //! Style has been changed
+        void ps_onStyleSheetsChanged();
+
     private:
         //! Clear
         void resetText();

src/blackgui/qss/stdwidget.qss

@@ -100,6 +100,10 @@ BlackGui--COverlayMessages {
   border-radius: 10px;
 }
 
+BlackGui--CDropSite {
+  background: black; /* background is background color here */
+}
+
 /*
 QTableView[isShowingLoadIndicator="true"] {
   background-image: url(:/preloaders/icons/preloaders/FillingRing64.gif);