fix wafer select bug

Change-Id: Ie48baac0d7e9d854d96302733b196f394e85e4ea

CameraMaterialGroupWnd/MaterialWindow/DieItem.cpp

@@ -11,9 +11,11 @@ DieItem::DieItem(int row, int col, PICK_DIE_STATUS status, qreal size, QGraphics
 
 void DieItem::setSelected(bool selected) {
     if (selected) {
-        setPen(QPen(Qt::green, 1));  // 选中时边框变为绿色
+        setPen(QPen(Qt::green, 0.5));  // 选中时边框变为绿色
+        setZValue(1);
     } else {
         setPen(QPen(Qt::black, 0.5));  // 未选中时恢复为黑色边框
+        setZValue(0);
     }
     qDebug() << "DieItem clicked: Row:" << row << "Col:" << col;
 }