Auto-select first item in layer mapping dialog

Fixes https://gitlab.com/kicad/code/kicad/issues/5942

pcbnew/dialogs/dialog_imported_layers.cpp

@@ -107,6 +107,9 @@ void DIALOG_IMPORTED_LAYERS::AddMappings()
     }
 
     DeleteListItems( rowsToDelete, m_unmatched_layers_list );
+
+    // Auto select the first item to improve ease-of-use
+    m_unmatched_layers_list->SetItemState( 0, wxLIST_STATE_SELECTED, wxLIST_STATE_SELECTED );
 }
 
 
@@ -238,6 +241,9 @@ DIALOG_IMPORTED_LAYERS::DIALOG_IMPORTED_LAYERS( wxWindow* aParent,
         ++row;
     }
 
+    // Auto select the first item to improve ease-of-use
+    m_unmatched_layers_list->SetItemState( 0, wxLIST_STATE_SELECTED, wxLIST_STATE_SELECTED );
+
     // Load the KiCad Layer names
     row = 0;
     LSEQ kicadLayersSeq = kiCadLayers.Seq();
@@ -253,6 +259,9 @@ DIALOG_IMPORTED_LAYERS::DIALOG_IMPORTED_LAYERS( wxWindow* aParent,
         ++row;
     }
 
+    // Auto select the first item to improve ease-of-use
+    m_kicad_layers_list->SetItemState( 0, wxLIST_STATE_SELECTED, wxLIST_STATE_SELECTED );
+
     m_sdbSizerOK->SetDefault();
 
     Fit();