https://lists.launchpad.net/kicad-developers/msg04973.html

eeschema/hotkeys.cpp

@@ -102,6 +102,7 @@ static Ki_HotkeyInfo HkRedo( wxT( "Redo" ), HK_REDO,
 #endif
 
 // Schematic editor
+static Ki_HotkeyInfo HkAddLabel( wxT( "add Label" ), HK_ADD_LABEL, 'L' );
 static Ki_HotkeyInfo HkBeginWire( wxT( "begin Wire" ), HK_BEGIN_WIRE, 'W' );
 static Ki_HotkeyInfo HkAddComponent( wxT( "Add Component" ),
                                      HK_ADD_NEW_COMPONENT, 'A' );
@@ -188,6 +189,7 @@ Ki_HotkeyInfo* s_Schematic_Hotkey_List[] =
     &HkEditComponentValue,
     &HkEditComponentFootprint,
     &HkBeginWire,
+    &HkAddLabel,
     NULL
 };
 
@@ -383,6 +385,13 @@ void WinEDA_SchematicFrame::OnHotKey( wxDC* DC, int hotkey,
         }
         break;
 
+    case HK_ADD_LABEL:
+        // switch to m_ID_current_state = ID_LABEL_BUTT;
+        if( m_ID_current_state != ID_LABEL_BUTT )
+            SetToolID( ID_LABEL_BUTT, wxCURSOR_PENCIL, _( "Add Label" ) );
+        OnLeftClick( DC, MousePos );
+        break;
+
     case HK_BEGIN_WIRE:
 
         /* An item is selected. If edited and not a wire, a new command is not

eeschema/hotkeys.h

@@ -31,7 +31,8 @@ enum hotkey_id_commnand {
     HK_COPY_COMPONENT_OR_LABEL,
     HK_DRAG,
     HK_ADD_NEW_COMPONENT,
-    HK_BEGIN_WIRE
+    HK_BEGIN_WIRE,
+    HK_ADD_LABEL
 };
 
 // List of hotkey descriptors for eeschema