diff --git a/dw/oofawarewidget.cc b/dw/oofawarewidget.cc
index 5e627d4..2cf4c15 100644
--- a/dw/oofawarewidget.cc
+++ b/dw/oofawarewidget.cc
@@ -195,8 +195,9 @@ void OOFAwareWidget::notifySetParent ()
            widget != NULL && oofContainer[oofmIndex] == NULL;
            widget = widget->getParent ())
          if (isOOFContainer (widget, oofmIndex)) {
-            assert (widget->instanceOf <OOFAwareWidget>());
-            oofContainer[oofmIndex] = (OOFAwareWidget*)widget;
+            auto *oaw= dynamic_cast< OOFAwareWidget * >( widget );
+            assert (oaw);
+            oofContainer[oofmIndex]= oaw;
          }
    
       DBG_OBJ_ARRSET_PTR ("oofContainer", oofmIndex, oofContainer[oofmIndex]);
diff --git a/dw/oofposrelmgr.cc b/dw/oofposrelmgr.cc
index f4f89ef..2c081cd 100644
--- a/dw/oofposrelmgr.cc
+++ b/dw/oofposrelmgr.cc
@@ -66,8 +66,8 @@ void OOFPosRelMgr::calcWidgetRefSize (Widget *widget, Requisition *size)
    // (Notice also that Widget::sizeRequest has to be called in all
    // cases.)
 
-   if (widget->instanceOf <OOFAwareWidget>())
-      *size = *((OOFAwareWidget*)widget)->getRequisitionWithoutOOF ();
+   if (auto *oaw= dynamic_cast< OOFAwareWidget * >( widget ))
+      *size = *oaw->getRequisitionWithoutOOF ();
 
    
    DBG_OBJ_LEAVE_VAL ("%d * (%d + %d)",
diff --git a/dw/table.cc b/dw/table.cc
index 03723a5..26aa904 100644
--- a/dw/table.cc
+++ b/dw/table.cc
@@ -607,8 +607,8 @@ AlignedTableCell *Table::getCellRef ()
       int n = curCol + row * numCols;
       if (childDefined (n)) {
          child = children->get(n)->cell.widget;
-         if (child->instanceOf <AlignedTableCell>())
-            return (AlignedTableCell*)child;
+         if (auto *atc= dynamic_cast< AlignedTableCell * >( child ))
+            return atc;
       }
    }
 
diff --git a/dw/textblock.cc b/dw/textblock.cc
index e8a82ec..b66b5c7 100644
--- a/dw/textblock.cc
+++ b/dw/textblock.cc
@@ -2763,12 +2763,11 @@ void Textblock::addParbreak (int space, core::style::Style *style)
          way that the space is in any case visible. */
       /* Find the widget where to adjust the breakSpace. (Only
          consider normal flow, no floats etc.) */
+      Textblock *textblock2= nullptr;
       for (Widget *widget = this;
-           widget->getParent() != NULL &&
-              widget->getParent()->instanceOf <Textblock>() &&
+              ( textblock2= dynamic_cast< Textblock * >( widget->getParent() ) ) &&
               !isWidgetOOF (widget);
            widget = widget->getParent ()) {
-         Textblock *textblock2 = (Textblock*)widget->getParent ();
          int index = textblock2->hasListitemValue ? 1 : 0;
          bool isfirst = (textblock2->words->getRef(index)->content.type
                          == core::Content::WIDGET_IN_FLOW
@@ -3192,9 +3191,9 @@ int Textblock::getGeneratorWidth ()
          int xRel;
          // We only examine instances of dw::Textblock, since they are relevant
          // for floats, for which this method is only called.
-         if(word->content.type == core::Content::WIDGET_IN_FLOW &&
-            word->content.widget->instanceOf<Textblock>()) {
-            Textblock *tbChild = (Textblock*)word->content.widget;
+         if(Textblock *tbChild= nullptr;
+            word->content.type == core::Content::WIDGET_IN_FLOW &&
+            ( tbChild= dynamic_cast< Textblock * >( word->content.widget ) )) {
             if(tbChild->findSizeRequestReference(this, &xRel, NULL))
                wChild = max(wChild, xRel + tbChild->getGeneratorWidth());
          }