Turn on zone visibility when you start drawing a zone

It's disconcerting to have the zone turn invisible when
you finish drawing and drop the selection.

pcbnew/pcb_base_edit_frame.cpp

@@ -205,6 +205,13 @@ void PCB_BASE_EDIT_FRAME::SetGridVisibility( bool aVisible )
 }
 
 
+void PCB_BASE_EDIT_FRAME::SetObjectVisible( GAL_LAYER_ID aLayer, bool aVisible )
+{
+    if( m_appearancePanel )
+        m_appearancePanel->SetObjectVisible( aLayer, aVisible );
+}
+
+
 COLOR_SETTINGS* PCB_BASE_EDIT_FRAME::GetColorSettings()
 {
     return Pgm().GetSettingsManager().GetColorSettings( GetPcbNewSettings()->m_ColorTheme );

pcbnew/pcb_base_edit_frame.h

@@ -168,6 +168,8 @@ public:
      */
     void SetGridVisibility( bool aVisible ) override;
 
+    void SetObjectVisible( GAL_LAYER_ID aLayer, bool aVisible = true );
+
     /**
      * Function GetRotationAngle()
      * Returns the angle used for rotate operations.

pcbnew/tools/drawing_tool.cpp

@@ -1753,6 +1753,9 @@ int DRAWING_TOOL::DrawZone( const TOOL_EVENT& aEvent )
     if( !getSourceZoneForAction( zoneMode, &sourceZone ) )
         return 0;
 
+    // Turn zones on if they are off, so that the created object will be visible after completion
+    m_frame->SetObjectVisible( LAYER_ZONES );
+
     ZONE_CREATE_HELPER::PARAMS params;
 
     params.m_keepout = drawMode == MODE::KEEPOUT;

pcbnew/widgets/appearance_controls.cpp

@@ -1039,12 +1039,14 @@ void APPEARANCE_CONTROLS::SetLayerVisible( LAYER_NUM aLayer, bool isVisible )
 
 void APPEARANCE_CONTROLS::SetObjectVisible( GAL_LAYER_ID aLayer, bool isVisible )
 {
-    // Currently only used for the grid, so we just update the ui
     if( m_objectSettingsMap.count( aLayer ) )
     {
         APPEARANCE_SETTING* setting = m_objectSettingsMap.at( aLayer );
         setting->ctl_visibility->SetValue( isVisible );
     }
+
+    m_frame->GetCanvas()->GetView()->SetLayerVisible( aLayer, isVisible );
+    m_frame->GetCanvas()->Refresh();
 }