Don't rebuild the whole nets grid on show/hide

Besides being slow, this causes the scroll position
of the grid to be lost.

pcbnew/tools/board_inspection_tool.cpp

@@ -1242,7 +1242,7 @@ void BOARD_INSPECTION_TOOL::doHideNet( int aNetCode, bool aHide )
     m_frame->GetCanvas()->RedrawRatsnest();
     m_frame->GetCanvas()->Refresh();
 
-    m_frame->GetAppearancePanel()->OnBoardNetSettingsChanged( *m_frame->GetBoard() );
+    m_frame->GetAppearancePanel()->OnNetVisibilityChanged( aNetCode, !aHide );
 }
 
 

pcbnew/widgets/appearance_controls.cpp

@@ -948,6 +948,18 @@ void APPEARANCE_CONTROLS::OnBoardNetSettingsChanged( BOARD& aBoard )
 }
 
 
+void APPEARANCE_CONTROLS::OnNetVisibilityChanged( int aNetCode, bool aVisibility )
+{
+    int row = m_netsTable->GetRowByNetcode( aNetCode );
+
+    if( row >= 0 )
+    {
+        m_netsTable->SetValueAsBool( row, NET_GRID_TABLE::COL_VISIBILITY, aVisibility );
+        m_netsGrid->ForceRefresh();
+    }
+}
+
+
 bool APPEARANCE_CONTROLS::doesBoardItemNeedRebuild( BOARD_ITEM* aBoardItem )
 {
     return aBoardItem->Type() == PCB_NETINFO_T;

pcbnew/widgets/appearance_controls.h

@@ -224,6 +224,9 @@ public:
     ///< Update the widget when the active board layer is changed.
     void OnLayerChanged();
 
+    /// Notifies the panel when a net has been hidden or shown via the external tool.
+    void OnNetVisibilityChanged( int aNetCode, bool aVisibility );
+
     ///< Manually update visibility for a given layer
     void SetLayerVisible( LAYER_NUM aLayer, bool isVisible );