Shutdown safety (KICAD-N5Y).

(cherry picked from commit 59caea4344)

eeschema/widgets/search_handlers.h

@@ -48,6 +48,9 @@ public:
 
     wxString GetResultCell( int aRow, int aCol ) override
     {
+        if( m_frame->IsClosing() )
+            return wxEmptyString;
+
         if( aRow >= static_cast<int>( m_hitlist.size() ) )
             return wxEmptyString;
 

include/eda_base_frame.h

@@ -589,6 +589,8 @@ public:
      */
     virtual void OnModify();
 
+    bool IsClosing() const { return m_isClosing; }
+
     bool NonUserClose( bool aForce )
     {
         m_isNonUserClose = true;

pcbnew/widgets/search_handlers.h

@@ -39,6 +39,9 @@ public:
 
     wxString GetResultCell( int aRow, int aCol ) override
     {
+        if( m_frame->IsClosing() )
+            return wxEmptyString;
+
         if( aRow >= static_cast<int>(m_hitlist.size() ) )
             return wxEmptyString;