[TD]fix Front lock icon in DPG

src/Mod/TechDraw/App/DrawProjGroupItem.cpp

@@ -102,6 +102,7 @@ void DrawProjGroupItem::onChanged(const App::Property *prop)
 bool DrawProjGroupItem::isLocked(void) const
 {
     bool isLocked = DrawView::isLocked();
+
     if (isAnchor()) {                             //Anchor view is always locked to DPG
         return true;
     }
@@ -112,6 +113,24 @@ bool DrawProjGroupItem::isLocked(void) const
     return isLocked;
 }
 
+bool DrawProjGroupItem::showLock(void) const
+{
+    bool result = DrawView::showLock();
+    DrawProjGroup* parent = getPGroup();
+    bool parentLock = false;
+    if (parent != nullptr) {
+        parentLock = parent->LockPosition.getValue();
+    }
+
+    if (isAnchor() &&                         //don't show lock for Front if DPG is not locked
+        !parentLock) { 
+        result = false;
+    }   
+
+    return result;
+}
+
+
 App::DocumentObjectExecReturn *DrawProjGroupItem::execute(void)
 {
     if (DrawUtil::checkParallel(Direction.getValue(),