RackWidget: only allow drag & drop if there is no preview on the board

qt/rack_widget.cpp

@@ -170,12 +170,24 @@ vector<Tile> RackWidget::filterRack(const vector<Tile> &iTiles) const
 // Drag & drop handling
 
 
+bool RackWidget::canStartDragDrop() const
+{
+    if (m_game == NULL || m_game->isFinished())
+        return false;
+    // Drag & drop is not allowed when a word is being played
+    return m_tiles.size() == m_filteredTiles.size();
+}
+
+
 void RackWidget::tilePressed(int row, int col, QMouseEvent *event)
 {
     ASSERT(row == 0, "Multi-line racks are not supported");
     ASSERT(col >= 0 && (unsigned)col < m_tilesVect.size(),
            "Invalid tile index: " << col);
 
+    if (!canStartDragDrop())
+        return;
+
     LOG_DEBUG("Starting drag for tile " << col);
 
     TileWidget *tileWidget = m_tilesVect[col];

qt/rack_widget.h

@@ -102,6 +102,8 @@ private:
      */
     vector<Tile> filterRack(const vector<Tile> &iTiles) const;
 
+    bool canStartDragDrop() const;
+
     /**
      * Return the 0-based index of the tile found at the given (relative)
      * position. If there is no such tile, return -1.