diff --git a/G940LEDControl/Forms/ButtonFunctionFrm.dfm b/G940LEDControl/Forms/ButtonFunctionFrm.dfm
index a4a0057..6e8825f 100644
--- a/G940LEDControl/Forms/ButtonFunctionFrm.dfm
+++ b/G940LEDControl/Forms/ButtonFunctionFrm.dfm
@@ -72,10 +72,13 @@ object ButtonFunctionForm: TButtonFunctionForm
     Header.Options = [hoAutoResize, hoColumnResize, hoDrag, hoShowSortGlyphs, hoVisible]
     TabOrder = 1
     TreeOptions.AutoOptions = [toAutoDropExpand, toAutoScrollOnExpand, toAutoSort, toAutoTristateTracking, toAutoDeleteMovedNodes]
+    TreeOptions.MiscOptions = [toAcceptOLEDrop, toFullRepaintOnResize, toInitOnSave, toWheelPanning, toEditOnClick]
     TreeOptions.PaintOptions = [toShowButtons, toShowDropmark, toShowTreeLines, toThemeAware, toUseBlendedImages]
     TreeOptions.SelectionOptions = [toFullRowSelect]
+    OnFocusChanged = vstFunctionsFocusChanged
     OnGetText = vstFunctionsGetText
     OnPaintText = vstFunctionsPaintText
+    ExplicitTop = 5
     Columns = <
       item
         Position = 0
@@ -98,9 +101,9 @@ object ButtonFunctionForm: TButtonFunctionForm
     TabOrder = 2
     object vstStates: TVirtualStringTree
       Left = 0
-      Top = 113
+      Top = 81
       Width = 411
-      Height = 239
+      Height = 271
       Align = alClient
       Header.AutoSizeIndex = 0
       Header.Font.Charset = DEFAULT_CHARSET
@@ -108,8 +111,16 @@ object ButtonFunctionForm: TButtonFunctionForm
       Header.Font.Height = -11
       Header.Font.Name = 'Tahoma'
       Header.Font.Style = []
+      Header.MainColumn = 1
       Header.Options = [hoAutoResize, hoColumnResize, hoDrag, hoShowSortGlyphs, hoVisible]
       TabOrder = 0
+      TreeOptions.MiscOptions = [toAcceptOLEDrop, toEditable, toFullRepaintOnResize, toInitOnSave, toToggleOnDblClick, toWheelPanning]
+      TreeOptions.PaintOptions = [toShowButtons, toShowDropmark, toThemeAware, toUseBlendedImages]
+      TreeOptions.SelectionOptions = [toExtendedFocus, toFullRowSelect]
+      OnChange = vstStatesChange
+      OnCreateEditor = vstStatesCreateEditor
+      OnEditing = vstStatesEditing
+      OnGetText = vstStatesGetText
       Columns = <
         item
           Position = 0
@@ -119,20 +130,20 @@ object ButtonFunctionForm: TButtonFunctionForm
         item
           Position = 1
           Width = 200
-          WideText = 'Color'
+          WideText = 'Colour'
         end>
     end
     object pnlName: TPanel
       Left = 0
       Top = 0
       Width = 411
-      Height = 113
+      Height = 81
       Align = alTop
       BevelOuter = bvNone
       TabOrder = 1
       DesignSize = (
         411
-        113)
+        81)
       object lblFunctionName: TLabel
         Left = 0
         Top = 19
@@ -157,11 +168,17 @@ object ButtonFunctionForm: TButtonFunctionForm
         Anchors = [akLeft, akTop, akRight]
         AutoSize = False
         Caption = 'runtime: category'
+        Font.Charset = DEFAULT_CHARSET
+        Font.Color = clGrayText
+        Font.Height = -11
+        Font.Name = 'Tahoma'
+        Font.Style = []
+        ParentFont = False
         ExplicitWidth = 401
       end
       object lblHasStates: TLabel
         Left = 0
-        Top = 74
+        Top = 47
         Width = 401
         Height = 31
         AutoSize = False
@@ -173,7 +190,7 @@ object ButtonFunctionForm: TButtonFunctionForm
       end
       object lblNoStates: TLabel
         Left = 0
-        Top = 55
+        Top = 47
         Width = 195
         Height = 13
         Caption = 'This function has no configurable states.'
diff --git a/G940LEDControl/Forms/ButtonFunctionFrm.pas b/G940LEDControl/Forms/ButtonFunctionFrm.pas
index 6c1c5b4..cb1b237 100644
--- a/G940LEDControl/Forms/ButtonFunctionFrm.pas
+++ b/G940LEDControl/Forms/ButtonFunctionFrm.pas
@@ -8,12 +8,18 @@ uses
   Vcl.Forms,
   Vcl.Graphics,
   Vcl.StdCtrls,
+  Winapi.Messages,
 
   VirtualTrees,
 
+  LEDFunctionIntf,
   Profile;
 
 
+const
+  WM_STARTEDITING = WM_USER + 1;
+
+
 type
   TButtonFunctionForm = class(TForm)
     pnlButtons: TPanel;
@@ -32,11 +38,22 @@ type
     procedure FormDestroy(Sender: TObject);
     procedure vstFunctionsGetText(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType; var CellText: string);
     procedure vstFunctionsPaintText(Sender: TBaseVirtualTree; const TargetCanvas: TCanvas; Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType);
+    procedure vstFunctionsFocusChanged(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex);
+    procedure vstStatesGetText(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType; var CellText: string);
+    procedure vstStatesChange(Sender: TBaseVirtualTree; Node: PVirtualNode);
+    procedure vstStatesCreateEditor(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex; out EditLink: IVTEditLink);
+    procedure vstStatesEditing(Sender: TBaseVirtualTree;
+      Node: PVirtualNode; Column: TColumnIndex; var Allowed: Boolean);
   private
     FButtonIndex: Integer;
     FProfile: TProfile;
+  protected
+    procedure WMStartEditing(var Msg: TMessage); message WM_STARTEDITING;
   protected
     procedure LoadFunctions;
+    procedure SetFunction(AProvider: ILEDFunctionProvider; AFunction: ILEDFunction);
+
+    procedure LoadStates(AFunction: ILEDMultiStateFunction);
 
     property ButtonIndex: Integer read FButtonIndex write FButtonIndex;
     property Profile: TProfile read FProfile write FProfile;
@@ -47,22 +64,36 @@ type
 
 implementation
 uses
-  System.SysUtils,
   Generics.Collections,
+  System.SysUtils,
+  Winapi.Windows,
 
-  LEDFunctionIntf,
-  LEDFunctionRegistry;
+  ColourEditor,
+  LEDFunctionRegistry,
+  LEDStateIntf;
 
 
 type
-  TNodeType = (ntCategory, ntFunction);
-  TNodeData = record
-    NodeType: TNodeType;
+  TFunctionNodeType = (ntCategory, ntFunction);
+  TFunctionNodeData = record
+    NodeType: TFunctionNodeType;
     Provider: ILEDFunctionProvider;
     LEDFunction: ILEDFunction;
   end;
 
-  PNodeData = ^TNodeData;
+  PFunctionNodeData = ^TFunctionNodeData;
+
+
+  TStateNodeData = record
+    State: ILEDState;
+  end;
+
+  PStateNodeData = ^TStateNodeData;
+
+
+const
+  ColumnState = 0;
+  ColumnColour = 1;
 
 
 {$R *.dfm}
@@ -84,9 +115,8 @@ end;
 
 procedure TButtonFunctionForm.FormCreate(Sender: TObject);
 begin
-  vstFunctions.NodeDataSize := SizeOf(TNodeData);
-
-  lblNoStates.Top := lblHasStates.Top;
+  vstFunctions.NodeDataSize := SizeOf(TFunctionNodeData);
+  vstStates.NodeDataSize := SizeOf(TStateNodeData);
 
   lblCategoryName.Caption := '';
   lblFunctionName.Caption := '';
@@ -108,7 +138,7 @@ var
   function GetCategoryNode(AProvider: ILEDFunctionProvider; AFunction: ILEDFunction): PVirtualNode;
   var
     category: string;
-    nodeData: PNodeData;
+    nodeData: PFunctionNodeData;
 
   begin
     category := AFunction.GetCategoryName;
@@ -130,7 +160,7 @@ var
 
 var
   node: PVirtualNode;
-  nodeData: PNodeData;
+  nodeData: PFunctionNodeData;
   provider: ILEDFunctionProvider;
   ledFunction: ILEDFunction;
 
@@ -162,10 +192,88 @@ begin
 end;
 
 
+procedure TButtonFunctionForm.SetFunction(AProvider: ILEDFunctionProvider; AFunction: ILEDFunction);
+var
+  multiStateFunction: ILEDMultiStateFunction;
+
+begin
+  lblCategoryName.Caption := AFunction.GetCategoryName;
+  lblFunctionName.Caption := AFunction.GetDisplayName;
+
+  if Supports(AFunction, ILEDMultiStateFunction, multiStateFunction) then
+  begin
+    lblNoStates.Visible := False;
+    lblHasStates.Visible := True;
+
+    LoadStates(multiStateFunction);
+    vstStates.Visible := True;
+  end else
+  begin
+    lblNoStates.Visible := True;
+    lblHasStates.Visible := False;
+
+    vstStates.Visible := False;
+    vstStates.Clear;
+  end;
+end;
+
+
+procedure TButtonFunctionForm.LoadStates(AFunction: ILEDMultiStateFunction);
+var
+  node: PVirtualNode;
+  nodeData: PStateNodeData;
+  state: ILEDState;
+
+begin
+  vstStates.BeginUpdate;
+  try
+    vstStates.Clear;
+
+    for state in AFunction do
+    begin
+      node := vstStates.AddChild(nil);
+      nodeData := vstStates.GetNodeData(node);
+      nodeData^.State := state;
+    end;
+  finally
+    vstStates.EndUpdate;
+  end;
+end;
+
+
+procedure TButtonFunctionForm.vstFunctionsFocusChanged(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex);
+var
+  nodeData: PFunctionNodeData;
+  functionNode: PVirtualNode;
+
+begin
+  if Assigned(Node) then
+  begin
+    nodeData := Sender.GetNodeData(Node);
+
+    case nodeData^.NodeType of
+      ntCategory:
+        begin
+          { Select first child (function) node instead }
+          functionNode := Sender.GetFirstChild(Node);
+          if not Assigned(functionNode) then
+            exit;
+
+          Sender.FocusedNode := functionNode;
+          Sender.Selected[functionNode] := True;
+        end;
+
+      ntFunction:
+        SetFunction(nodeData^.Provider, nodeData^.LEDFunction);
+    end;
+  end;
+end;
+
+
 procedure TButtonFunctionForm.vstFunctionsGetText(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex;
                                                   TextType: TVSTTextType; var CellText: string);
 var
-  nodeData: PNodeData;
+  nodeData: PFunctionNodeData;
 
 begin
   nodeData := Sender.GetNodeData(Node);
@@ -180,7 +288,7 @@ end;
 procedure TButtonFunctionForm.vstFunctionsPaintText(Sender: TBaseVirtualTree; const TargetCanvas: TCanvas;
                                                     Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType);
 var
-  nodeData: PNodeData;
+  nodeData: PFunctionNodeData;
 
 begin
   nodeData := Sender.GetNodeData(Node);
@@ -191,4 +299,49 @@ begin
     TargetCanvas.Font.Style := [];
 end;
 
+
+procedure TButtonFunctionForm.vstStatesGetText(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex;
+                                               TextType: TVSTTextType; var CellText: string);
+var
+  nodeData: PStateNodeData;
+
+begin
+  nodeData := Sender.GetNodeData(Node);
+
+  case Column of
+    ColumnState:    CellText := nodeData^.State.GetDisplayName;
+    ColumnColour:   CellText := 'Red';
+  end;
+end;
+
+
+procedure TButtonFunctionForm.vstStatesChange(Sender: TBaseVirtualTree; Node: PVirtualNode);
+begin
+  if Assigned(Node) and not (tsIncrementalSearching in Sender.TreeStates) then
+    PostMessage(Self.Handle, WM_STARTEDITING, WPARAM(Node), 0);
+end;
+
+
+procedure TButtonFunctionForm.vstStatesCreateEditor(Sender: TBaseVirtualTree; Node: PVirtualNode;
+                                                    Column: TColumnIndex; out EditLink: IVTEditLink);
+begin
+  EditLink := TVTColourEditor.Create;
+end;
+
+
+procedure TButtonFunctionForm.vstStatesEditing(Sender: TBaseVirtualTree;
+  Node: PVirtualNode; Column: TColumnIndex; var Allowed: Boolean);
+begin
+  Allowed := True;
+end;
+
+procedure TButtonFunctionForm.WMStartEditing(var Msg: TMessage);
+var
+  node: PVirtualNode;
+
+begin
+  node := Pointer(Msg.WParam);
+  vstStates.EditNode(Node, 1);
+end;
+
 end.
diff --git a/G940LEDControl/G940LEDControl.dpr b/G940LEDControl/G940LEDControl.dpr
index da5f91d..0bba2da 100644
--- a/G940LEDControl/G940LEDControl.dpr
+++ b/G940LEDControl/G940LEDControl.dpr
@@ -29,7 +29,8 @@ uses
   FSXLEDFunction in 'Units\FSXLEDFunction.pas',
   StaticResources in 'Units\StaticResources.pas',
   FSXResources in 'Units\FSXResources.pas',
-  FSXSimConnectClient in 'Units\FSXSimConnectClient.pas';
+  FSXSimConnectClient in 'Units\FSXSimConnectClient.pas',
+  ColourEditor in 'Units\ColourEditor.pas';
 
 {$R *.res}
 
diff --git a/G940LEDControl/G940LEDControl.dproj b/G940LEDControl/G940LEDControl.dproj
index 5638f7d..4c8b157 100644
--- a/G940LEDControl/G940LEDControl.dproj
+++ b/G940LEDControl/G940LEDControl.dproj
@@ -195,6 +195,7 @@
 			<DCCReference Include="Units\StaticResources.pas"/>
 			<DCCReference Include="Units\FSXResources.pas"/>
 			<DCCReference Include="Units\FSXSimConnectClient.pas"/>
+			<DCCReference Include="Units\ColourEditor.pas"/>
 			<BuildConfiguration Include="Debug">
 				<Key>Cfg_2</Key>
 				<CfgParent>Base</CfgParent>
diff --git a/G940LEDControl/Units/ColourEditor.pas b/G940LEDControl/Units/ColourEditor.pas
new file mode 100644
index 0000000..2daf26d
--- /dev/null
+++ b/G940LEDControl/Units/ColourEditor.pas
@@ -0,0 +1,141 @@
+unit ColourEditor;
+
+interface
+uses
+  System.Types,
+  System.Classes,
+  Vcl.StdCtrls,
+  Winapi.Messages,
+
+  VirtualTrees;
+
+
+type
+  TVTColourEditor = class(TInterfacedObject, IVTEditLink)
+  private
+    FEdit: TComboBox;
+    FTree: TBaseVirtualTree;
+    FColumn: TColumnIndex;
+  protected
+    procedure EditKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
+  protected
+    { IVTEditLink }
+    function BeginEdit: Boolean; stdcall;
+    function CancelEdit: Boolean; stdcall;
+    function EndEdit: Boolean; stdcall;
+
+    function PrepareEdit(Tree: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex): Boolean; stdcall;
+    procedure ProcessMessage(var Message: TMessage); stdcall;
+
+    function GetBounds: TRect; stdcall;
+    procedure SetBounds(R: TRect); stdcall;
+  public
+    destructor Destroy; override;
+  end;
+
+implementation
+uses
+  System.SysUtils,
+  Winapi.Windows;
+
+
+{ TVTColourEditor }
+destructor TVTColourEditor.Destroy;
+begin
+  FreeAndNil(FEdit);
+
+  inherited;
+end;
+
+
+function TVTColourEditor.BeginEdit: Boolean;
+begin
+  Result := True;
+  FEdit.Show;
+  FEdit.SetFocus;
+end;
+
+
+function TVTColourEditor.CancelEdit: Boolean;
+begin
+  Result := True;
+  FEdit.Hide;
+end;
+
+
+function TVTColourEditor.EndEdit: Boolean;
+begin
+  Result := True;
+  // TODO update node data
+end;
+
+
+function TVTColourEditor.PrepareEdit(Tree: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex): Boolean;
+begin
+  Result := True;
+
+  FTree := Tree;
+//  FNode := Node;
+  FColumn := Column;
+
+  FreeAndNil(FEdit);
+
+  FEdit := TComboBox.Create(nil);
+  FEdit.Visible := False;
+  FEdit.Parent := Tree;
+
+//  FEdit.Text := Data.Value;
+//  FEdit.Items.Add();
+
+  FEdit.OnKeyDown := EditKeyDown;
+end;
+
+
+procedure TVTColourEditor.ProcessMessage(var Message: TMessage);
+begin
+  FEdit.WindowProc(Message);
+end;
+
+
+function TVTColourEditor.GetBounds: TRect;
+begin
+  Result := FEdit.BoundsRect;
+end;
+
+
+procedure TVTColourEditor.SetBounds(R: TRect);
+var
+  dummy: Integer;
+
+begin
+  (FTree as TVirtualStringTree).Header.Columns.GetColumnBounds(FColumn, dummy, R.Right);
+  FEdit.BoundsRect := R;
+end;
+
+
+procedure TVTColourEditor.EditKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
+begin
+  case Key of
+    VK_ESCAPE:
+      begin
+        FTree.CancelEditNode;
+        Key := 0;
+      end;
+
+    VK_RETURN:
+      begin
+        FTree.EndEditNode;
+        Key := 0;
+      end;
+
+    VK_UP,
+    VK_DOWN:
+      if (Shift = []) and (not FEdit.DroppedDown) then
+      begin
+        PostMessage(FTree.Handle, WM_KEYDOWN, Key, 0);
+        Key := 0;
+      end;
+  end;
+end;
+
+end.